Elasticsearch, Logstash, Kibana or ELK Crash Course 101

Elasticsearch, Logstash, Kibana or ELK Crash Course 101

Prologue aka Disclaimer

This blog post is the outcome of a Hackerspace Event:: Logstash Intro Course that happened a few days ago. I prefer doing workshops Vs presentations -as I pray to the Live-Coding Gods- and this is the actual workshop in bulletin notes.


For our technical goal we will use my fail2ban !
We will figure (together) whom I ban with my fail2ban!!!

The results we want to present are:

Date IP Country

To help you with this inquiry, we will use this dataset: fail2ban.gz

If you read though this log you will see that it’s a grep from my messages logs.
So in the begging we have messages from compressed files … and in the end we have messages from uncompressed files.

But … Let’s begin with our journey !!


For our little experiment we need Java

I Know, I know … not the beverage - the programming language !!

try java 1.7.x

# java -version
java version "1.7.0_111"
OpenJDK Runtime Environment (IcedTea 2.6.7) (Arch Linux build 7.u111_2.6.7-1-x86_64)
OpenJDK 64-Bit Server VM (build 24.111-b01, mixed mode)

In my archlinux machine:

# yes | pacman -S jdk7-openjdk


As, October 26, 2016 all versions (logstash,elastic,kibana) are all in version 5.0.x and latests.
But we will try the well-known installed previous versions !!!

as from 5.0.x and later …. we have: Breaking changes and you will need Java 8


Let’s download software

# wget -c

# wget -c

# wget -c


Uncompress and test that logstash can run without a problem:

# unzip
# cd logstash-2.4.1

# logstash-2.4.1/
# ./bin/logstash --version
logstash 2.4.1

# ./bin/logstash --help

Basic Logstash Example

Reminder: Ctrl+c breaks the logstash

# ./bin/logstash -e 'input { stdin { } } output { stdout {} }'

We are now ready to type ‘Whatever’ and see what happens:

# ./bin/logstash -e 'input { stdin { } } output { stdout {} }'
Settings: Default pipeline workers: 4
Pipeline main started


2016-11-15T19:18:09.638Z myhomepc whatever

Ctrl + c
Ctrl + c

^CSIGINT received. Shutting down the agent. {:level=>:warn}
stopping pipeline {:id=>"main"}
Received shutdown signal, but pipeline is still waiting for in-flight events
to be processed. Sending another ^C will force quit Logstash, but this may cause
data loss. {:level=>:warn}
^CSIGINT received. Terminating immediately.. {:level=>:fatal}

Standard Input and Standard Output

In this first example the input is our standard input, that means keyboard
and standard output means our display.

We typed:


and logstash reports:

2016-11-15T19:18:09.638Z myhomepc whatever

There are three (3) fields:

  1. timestamp : 2016-11-15T19:18:09.638Z
  2. hostname : myhomepc
  3. message : whatever

Logstash Architecture


Logstash architecture reminds me Von Neumann .

Input --> Process --> Output 

In Process we have filter plugins and in input pluggins & output plugins we have codec plugins

Codec plugins

We can define the data representation (logs or events) via codec plugins. Most basic codec plugin is: rubydebug


eg. logstash -e ‘input { stdin { } } output { stdout { codec => rubydebug} }’

# ./bin/logstash -e 'input { stdin { } } output { stdout { codec => rubydebug} }'
Settings: Default pipeline workers: 4
Pipeline main started


       "message" => "whatever",
      "@version" => "1",
    "@timestamp" => "2016-11-15T19:40:46.070Z",
          "host" => "myhomepc"

^CSIGINT received. Shutting down the agent. {:level=>:warn}
stopping pipeline {:id=>"main"}
^CSIGINT received. Terminating immediately.. {:level=>:fatal}


Let’s try the json codec plugin, but now we will try it via a linux pipe:

# echo whatever | ./bin/logstash -e 'input { stdin { } } output { stdout { codec => json }  }' 

Settings: Default pipeline workers: 4
Pipeline main started


Pipeline main has been shutdown
stopping pipeline {:id=>"main"}


# echo -e 'whatever1nwhatever2nn' | ./bin/logstash -e 'input { stdin { } } output { stdout { codec => json_lines }  }'

Settings: Default pipeline workers: 4
Pipeline main started


Pipeline main has been shutdown
stopping pipeline {:id=>"main"}

List of codec

Here is the basic list of codec:


Configuration File

It is now very efficient to run everything from the command line, so we will try to move to a configuration file:


input {
    stdin { }

output {
    stdout {
        codec => rubydebug

and run the above example once more:

# echo -e 'whatever1nwhatever2' | ./bin/logstash -f logstash.conf 

Settings: Default pipeline workers: 4
Pipeline main started

       "message" => "whatever1",
      "@version" => "1",
    "@timestamp" => "2016-11-15T19:59:51.146Z",
          "host" => "myhomepc"
       "message" => "whatever2",
      "@version" => "1",
    "@timestamp" => "2016-11-15T19:59:51.295Z",
          "host" => "myhomepc"

Pipeline main has been shutdown
stopping pipeline {:id=>"main"}

Config Test

Every time you need to test your configuration file for syntax check:

./bin/logstash --configtest

Configuration OK

fail2ban - logstash 1st try

Now it’s time to test our fail2ban file against our logstash setup. To avoid the terror of 22k lines, we will test the first 10 lines to see how it works:

# head ../fail2ban | ./bin/logstash -f logstash.conf

Settings: Default pipeline workers: 4
Pipeline main started

       "message" => "messages-20160918.gz:Sep 11 09:13:13 myhostname fail2ban.actions[1510]: NOTICE [apache-badbots] Unban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.784Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 09:51:08 myhostname fail2ban.actions[1510]: NOTICE [apache-badbots] Unban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.966Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 11:51:24 myhostname fail2ban.filter[1510]: INFO [apache-badbots] Found",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.967Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 11:51:24 myhostname fail2ban.actions[1510]: NOTICE [apache-badbots] Ban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.968Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 14:58:35 myhostname fail2ban.filter[1510]: INFO [postfix-sasl] Found",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.968Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 14:58:36 myhostname fail2ban.actions[1510]: NOTICE [postfix-sasl] Ban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.969Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 15:03:08 myhostname fail2ban.filter[1510]: INFO [apache-fakegooglebot] Ignore by command",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.970Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 15:03:08 myhostname fail2ban.filter[1510]: INFO [apache-fakegooglebot] Ignore by command",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.970Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 15:26:04 myhostname fail2ban.filter[1510]: INFO [apache-fakegooglebot] Ignore by command",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.971Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 17:01:02 myhostname fail2ban.filter[1510]: INFO [apache-badbots] Found",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:10:40.971Z",
          "host" => "myhomepc"

Pipeline main has been shutdown
stopping pipeline {:id=>"main"}

fail2ban - filter

As we said in the begging of our journey, we want to check what IPs I Ban with fail2ban !!
So we need to filter the messages. Reading through our dataset, we will soon find out that we need lines like:

"messages-20160918.gz:Sep 11 11:51:24 myhostname fail2ban.actions[1510]: NOTICE [apache-badbots] Ban"

so we could use an if-statement (conditional statements).

fail2ban - Conditionals

You can use the following comparison operators:

    equality: ==, !=, <, >, <=, >=
    regexp: =~, !~ (checks a pattern on the right against a string value on the left)
    inclusion: in, not in 

The supported boolean operators are:

    and, or, nand, xor 

The supported unary operators are:


Expressions can be long and complex.

fail2ban - message filter

With the above knowledge, our logstash configuration file can now be:


input {
    stdin { }

filter {
    if [message]  !~ ' Ban ' {
        drop { }

output {
    stdout {
        codec => rubydebug

and the results:

# head ../fail2ban | ./bin/logstash -f logstash.conf -v

       "message" => "messages-20160918.gz:Sep 11 11:51:24 myhostname fail2ban.actions[1510]: NOTICE [apache-badbots] Ban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:33:39.858Z",
          "host" => "myhomepc"
       "message" => "messages-20160918.gz:Sep 11 14:58:36 myhostname fail2ban.actions[1510]: NOTICE [postfix-sasl] Ban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T20:33:39.859Z",
          "host" => "myhomepc"

but we are pretty far away from our goal.

The above approach is just fine for our example, but it is far away from perfect or even elegant !
And here is way: the regular expression ‘ Ban ‘ is just that, a regular expression.

The most elegant approach is to match the entire message and drop everything else. Then we could be most certain sure about the output of the logs.


And here comes grok !!!

and to do that we must learn the grok:

Parses unstructured event data into fields

that would be extremely useful. Remember, we have a goal!
We dont need everything, we need the date, ip & country !!

Grok Patterns

grok work with patterns, that follows the below generic rule:


You can use the online grok debugger: grok heroku
to test your messages/logs/events against grok patterns

If you click on the left grok-patterns you will see the most common grok patterns.

In our setup:

# find . -type d -name patterns

the latest directory is where our logstansh instance keeps the default grok patterns.

To avoid the suspense … here is the full grok pattern:


grok - match

If you run this new setup, we will see something peculiar:


input {
    stdin { }

filter {

#    if [message]  !~ ' Ban ' {
#        drop { }
#    }

    grok {
        match => {
            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP} %{HOSTNAME} %{SYSLOGPROG}: %{LOGLEVEL} [%{PROG}] Ban %{IPV4}"

output {
    stdout {
        codec => rubydebug

We will get messages like these:

       "message" => "messages:Nov 15 17:49:09 myhostname fail2ban.actions[1585]: NOTICE [apache-fakegooglebot] Ban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T21:30:29.345Z",
          "host" => "myhomepc",
       "program" => "fail2ban.actions",
           "pid" => "1585"
       "message" => "messages:Nov 15 17:49:31 myhostname fail2ban.action[1585]: ERROR /etc/fail2ban/filter.d/ignorecommands/apache-fakegooglebot -- stdout: ''",
      "@version" => "1",
    "@timestamp" => "2016-11-15T21:30:29.346Z",
          "host" => "myhomepc",
          "tags" => [
        [0] "_grokparsefailure"

It match some of them and the all the rest are tagged with grokparsefailure

We can remove them easily:


input {
    stdin { }

filter {

#    if [message]  !~ ' Ban ' {
#        drop { }
#    }

    grok {
        match => {
            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP} %{HOSTNAME} %{SYSLOGPROG}: %{LOGLEVEL} [%{PROG}] Ban %{IPV4}"

    if "_grokparsefailure" in [tags] {
        drop { }

output {
    stdout {
        codec => rubydebug

Using colon (:) character on SYNTAX grok pattern is a new field for grok / logstash.
So we can change a little bit the above grok pattern to this:


but then again, we want to filter some fields, like the date and IP, so

messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] Ban %{IPV4:ip}


input {
    stdin { }

filter {

#    if [message]  !~ ' Ban ' {
#        drop { }
#    }

    grok {
        match => {
            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] Ban %{IPV4:ip}"

    if "_grokparsefailure" in [tags] {
        drop { }

output {
    stdout {
        codec => rubydebug

output will be like this:

       "message" => "messages:Nov 15 17:49:32 myhostname fail2ban.actions[1585]: NOTICE [apache-fakegooglebot] Ban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T21:42:21.260Z",
          "host" => "myhomepc",
          "date" => "Nov 15 17:49:32",
            "ip" => ""

grok - custom pattern

If we want to match something specific with to a custom grok pattern, we can simple add one!

For example, we want to match Ban and Unban action:

# vim ./vendor/bundle/jruby/1.9/gems/logstash-patterns-core-2.0.5/patterns/ebal
ACTION (Ban|Unban)

and then our grok matching line will transform to :


input {
    stdin { }

filter {

#    if [message]  !~ ' Ban ' {
#        drop { }
#    }

    grok {
        match => {
#            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] Ban %{IPV4:ip}"
            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] %{ACTION:action} %{IPV4:ip}"

    if "_grokparsefailure" in [tags] {
        drop { }

output {
    stdout {
        codec => rubydebug


       "message" => "messages:Nov 15 18:13:53 myhostname fail2ban.actions[1585]: NOTICE [apache-badbots] Unban",
      "@version" => "1",
    "@timestamp" => "2016-11-15T21:53:59.634Z",
          "host" => "myhomepc",
          "date" => "Nov 15 18:13:53",
        "action" => "Unban",
            "ip" => ""


We are getting pretty close … the most difficult part is over (grok patterns).
Just need to remove any exta fields. We can actually do that with two ways:

  1. grok - remove_field
  2. mutate -remove_field

We’ll try mutate cause is more powerful.

And for our example/goal we will not use any custom extra Action field, so:


input {
    stdin { }

filter {

#    if [message]  !~ ' Ban ' {
#        drop { }
#    }

    grok {
        match => {
            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] Ban %{IPV4:ip}"
#            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] %{ACTION:action} %{IPV4:ip}"

    if "_grokparsefailure" in [tags] {
        drop { }
    mutate {
        remove_field => [ "message", "@version", "@timestamp", "host" ]

output {
    stdout {
        codec => rubydebug


    "date" => "Nov 15 17:49:32",
      "ip" => ""

so close !!!

mutate - replace

According to syslog RFC (request for comments) [RFC 3164 - RFC 3195]:

 In particular, the timestamp has a year, making it a nonstandard format

so most of logs doesnt have a YEAR on their timestamp !!!

Logstash can add an extra field or replace an existing field :


input {
    stdin { }

filter {

#    if [message]  !~ ' Ban ' {
#        drop { }
#    }

    grok {
        match => {
            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] Ban %{IPV4:ip}"
#            "message" => "messages%{DATA}:%{SYSLOGTIMESTAMP:date} %{HOSTNAME} %{PROG}(?:[%{POSINT}])?: %{LOGLEVEL} [%{PROG}] %{ACTION:action} %{IPV4:ip}"

    if "_grokparsefailure" in [tags] {
        drop { }
    mutate {
        remove_field => [ "message", "@version", "@timestamp", "host" ]
        replace => { date => "%{+YYYY} %{date}" }

output {
    stdout {
        codec => rubydebug

the output:

    "date" => "2016 Nov 15 17:49:32",
      "ip" => ""


The only thing that is missing from our original goal, is the country field!

Logstash has a geoip plugin that works perfectly with MaxMind

So we need to download the GeoIP database:

# wget -N

The best place is to put this file (uncompressed) under your logstash directory.

Now, it’s time to add the geoip support to the logstash.conf :

  # Add Country Name
  # wget -N
  geoip {
    source => "ip"
    target => "geoip"
    fields => ["country_name"]
    database => "GeoIP.dat"
   # database => "/etc/logstash/GeoIP.dat"

the above goes under the filter section of logstash conf file.

running the above configuration

# head ../fail2ban | ./bin/logstash -f logstash.conf

should display something like this:

     "date" => "2016 Sep 11 11:51:24",
       "ip" => "",
    "geoip" => {
        "country_name" => "Netherlands"
     "date" => "2016 Sep 11 14:58:36",
       "ip" => "",
    "geoip" => {
        "country_name" => "Russian Federation"

We are now pretty close to our primary objective.


It would be nice to somehow translate the geoip –> country_name to something more useful, like Country.

That’s why we are going to use the rename setting under the mutate plugin:

  mutate {
    rename => { "[geoip][country_name]"  => "Country" }

so let’s put all them together:

    geoip {
        source => "ip"
        target => "geoip"
        fields => ["country_name"]
        database => "GeoIP.dat"

    mutate {
        rename => { "[geoip][country_name]"  => "Country" }
        remove_field => [ "message", "@version", "@timestamp", "host", "geoip"]
        replace => { date => "%{+YYYY} %{date}" }

test run it and the output will show you something like that:

       "date" => "2016 Sep 11 11:51:24",
         "ip" => "",
    "Country" => "Netherlands"
       "date" => "2016 Sep 11 14:58:36",
         "ip" => "",
    "Country" => "Russian Federation"

hurray !!!

finally we have completed our primary objective.

Input - Output

Input File

Until now, you have been reading from the standard input, but it’s time to read from the file.
To do so, we must add the bellow settings under the input section:

file {
    path => "/var/log/messages"
    start_position => "beginning"

Testing our configuration file (without giving input from the command line):

./bin/logstash -f logstash.conf

and the output will be something like this:

       "path" => "/var/log/messages",
       "date" => "2016 Nov 15 17:49:09",
         "ip" => "",
    "Country" => "United States"
       "path" => "/var/log/messages",
       "date" => "2016 Nov 15 17:49:32",
         "ip" => "",
    "Country" => "United States"

so by changing the input from the standard input to a file path, we added a new extra filed.
The path

Just remove it with mutate –> remove_field as we already shown above


Now it’s time to send everything to our elastic search engine:

output {

    # stdout {
    #    codec => rubydebug
    # }

    elasticsearch {


Be Careful: In our above examples we have removed the timestamp field
but for the elasticsearch to work, we must enable it again:

remove_field => [ "message", "@version", "host", "geoip"]


Uncompress and run elastic search engine:

# unzip
# cd elasticsearch-2.4.1/
# ./bin/elasticsearch

elasticsearch is running under:

tcp6       0      0          :::*                    LISTEN      27862/java
tcp6       0      0          :::*                    LISTEN      27862/java

Impressive, but that’s it!


Let’s find out if the elasticsearch engine is running:

$ curl 'localhost:9200/_cat/health?v'

$ curl -XGET 'http://localhost:9200/_cluster/health?pretty=true'

epoch      timestamp cluster       status shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1482421814 17:50:14  elasticsearch yellow          1         1      1   1    0    0        1             0                  -                 50.0% 

$ curl 'localhost:9200/_cat/nodes?v'

host      ip        heap.percent ram.percent load node.role master name            7          98 0.50 d         *      Hazmat 

# curl -s -XGET 'http://localhost:9200/_cluster/health?level=indices' | jq .


Now it’s time to send our data to our elastic search engine, running the logstash daemon with input the fail2ban file and output the elastic search.


We are almost done. There is only one more step to our 101 course for ELK infrastructure.

And that is the kibana dashboard.

setup kibana

Uncompress and run the kibana dashboard:

 tar xf kibana-4.6.3-linux-x86_64.tar.gz


Now simply, open the kibana dashboard on:





enlarge your disk image aka windows extend volume

A visual guide on how to enlarge your windows disk image aka windows extend volume

I have a windows 10 qemu-kvm virtual machine for business purposes.
Every now and then, I have to resize it’s disk image!

This is my visual guide, so next time I will not waste any time figure this out, again!

Resize Disk image

The first step is to resize the disk image from the command line:

# ls -l win10.qcow2
-rw-r--r-- 1 root root 58861813760 Nov 17 10:04 win10.qcow2

# du -h win10.qcow2
55G win10.qcow2

#  qemu-img info win10.qcow2
image: win10.qcow2
file format: qcow2
virtual size: 55G (59055800320 bytes)
disk size: 55G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false
#  qemu-img resize win10.qcow2 +10G
Image resized.
# qemu-img info win10.qcow2
image: win10.qcow2
file format: qcow2
virtual size: 65G (69793218560 bytes)
disk size: 55G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false

Windows Problem - extend volume

Windows can not extend a volume if the free partition is not next to the “need-to-be” extened volume.


So we have to move the free partition next to C: drive

System Rescue Cd

Here comes system rescue cd !



with gparted you can move to the end of the virtual disk the ntfs recovery partition:









Computer Management - Disk Management

It’s time to extend our partition:







Tag(s): kvm, qemu, windows
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Linux Raid mdadm md0

Linux Raid

This blog post is created as a mental note for future reference

Linux Raid is the de-facto way for decades in the linux-world on how to create and use a software raid. RAID stands for: Redundant Array of Independent Disks. Some people use the I for inexpensive disks, I guess that works too!

In simple terms, you can use a lot of hard disks to behave as one disk with special capabilities!

You can use your own inexpensive/independent hard disks as long as they have the same geometry and you can do almost everything. Also it’s pretty easy to learn and use linux raid. If you dont have the same geometry, then linux raid will use the smallest one from your disks. Modern methods, like LVM and BTRFS can provide an abstract layer with more capabilities to their users, but some times (or because something you have built a loooong time ago) you need to go back to basics.

And every time -EVERY time- I am searching online for all these cool commands that those cool kids are using. Cause what’s more exciting than replacing your -a decade ago- linux raid setup this typical Saturday night?

Identify your Hard Disks

% find /sys/devices/ -type f -name model -exec cat {} \;

% lsblk
sda      8:0    0 931.5G  0 disk
sdb      8:16   0 931.5G  0 disk
sdc      8:32   0 931.5G  0 disk  


sda   disk  931.5G ST1000DX001-1CM1
sdb   disk  931.5G ST1000DX001-1CM1
sdc   disk  931.5G ST1000DX001-1CM1

Create a RAID-5 with 3 Disks

Having 3 hard disks of 1T size, we are going to use the raid-5 Level . That means that we have 2T of disk usage and the third disk with keep the parity of the first two disks. Raid5 provides us with the benefit of loosing one hard disk without loosing any data from our hard disk scheme.


% mdadm -C -v /dev/md0 --level=5 --raid-devices=3 /dev/sda /dev/sdb /dev/sdc 

mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: sze set to 5238784K
mdadm: Defaulting to version 1.2 metadata
md/raid:md0 raid level 5 active with 2 our of 3 devices, algorithm 2
mdadm: array /dev/md0 started.

% cat /proc/mdstat

Personalities : [raid6] [raid5] [raid4]
md0: active raid5 sdc[3] sdb[2] sda[1]
        10477568 blocks super 1.2 level 5, 512k chink, algorith 2 [3/3] [UUU]

unused devices: <none>

running lsblk will show us our new scheme:

sda   disk  931.5G ST1000DX001-1CM1
md0   raid5   1.8T
sdb   disk  931.5G ST1000DX001-1CM1
md0   raid5   1.8T
sdc   disk  931.5G ST1000DX001-1CM1
md0   raid5   1.8T

Save the Linux Raid configuration into a file

Software linux raid means that the raid configuration is actually ON the hard disks. You can take those 3 disks and put them to another linux box and everything will be there!! If you are keeping your operating system to another harddisk, you can also change your linux distro from one to another and your data will be on your linux raid5 and you can access them without any extra software from your new linux distro.

But it is a good idea to keep the basic conf to a specific configuration file, so if you have hardware problems your machine could understand what type of linux raid level you need to have on those broken disks!

% mdadm --detail --scan >> /etc/mdadm.conf

% cat /etc/mdadm.conf
ARRAY /dev/md0 metadata=1.2 name=MyServer:0 UUID=ef5da4df:3e53572e:c3fe1191:925b24cf

UUID - Universally Unique IDentifier

Be very careful that the above UUID is the UUID of the linux raid on your disks.
We have not yet created a filesystem over this new disk /dev/md0 and if you need to add this filesystem under your fstab file you can not use the UUID of the linux raid md0 disk.

Below there is an example on my system:

% blkid
/dev/sda: UUID="ef5da4df-3e53-572e-c3fe-1191925b24cf" UUID_SUB="f4e1da17-e4ff-74f0-b1cf-6ec86eca3df1" LABEL="MyServer:0" TYPE="linux_raid_member"
/dev/sdb: UUID="ef5da4df-3e53-572e-c3fe-1191925b24cf" UUID_SUB="ad7315e5-56ce-bd8c-75c5-0a72893a63db" LABEL="MyServer:0" TYPE="linux_raid_member"
/dev/sdc: UUID="ef5da4df-3e53-572e-c3fe-1191925b24cf" UUID_SUB="a90e317e-4384-8f30-0de1-ee77f8912610" LABEL="MyServer:0" TYPE="linux_raid_member" 

/dev/md0: LABEL="data" UUID="48fc963a-2128-4d35-85fb-b79e2546dce7" TYPE="ext4" 

% cat /etc/fstab

UUID=48fc963a-2128-4d35-85fb-b79e2546dce7   /backup auto    defaults    0   0

Replacing a hard disk

Hard disks will fail you. This is a fact that every sysadmin knows from day one. Systems will fail at some point in the future. So be prepared and keep backups !!

Failing a disk

Now it’s time to fail (if not already) the disk we want to replace:

% mdadm --manage /dev/md0 --fail /dev/sdb
mdadm: set /dev/sdb faulty in /dev/md0

Remove a broken disk

Here is a simple way to remove a broken disk from your linux raid configuration. Remember with raid5 level we can manage with 2 hard disks.

% mdadm --manage /dev/md0 --remove /dev/sdb
mdadm: hot removed /dev/sdb from /dev/md0

% cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sda[1] sdc[3]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [_UU]

unused devices: <none>

dmesg shows:

% dmesg | tail

md: data-check of RAID array md0
md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for data-check.
md: using 128k window, over a total of 976631296k.
md: md0: data-check done.
md/raid:md0: Disk failure on sdb, disabling device.
md/raid:md0: Operation continuing on 2 devices.
RAID conf printout:
 --- level:5 rd:3 wd:2
 disk 0, o:0, dev:sda
 disk 1, o:1, dev:sdb
 disk 2, o:1, dev:sdc
RAID conf printout:
 --- level:5 rd:3 wd:2
 disk 0, o:0, dev:sda
 disk 2, o:1, dev:sdc
md: unbind<sdb>
md: export_rdev(sdb)

Adding a new disk - replacing a broken one

Now it’s time to add a new and (if possible) clean hard disk. Just to be sure, I always wipe with dd the first few kilobytes of every disk with zeros.

Using mdadm to add this new disk:

# mdadm --manage /dev/md0 --add /dev/sdb
mdadm: added /dev/sdb

% cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdb[4] sda[1] sdc[3]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [_UU]
      [>....................]  recovery =  0.2% (2753372/976631296) finish=189.9min speed=85436K/sec

unused devices: <none>

For a 1T Hard Disk is about 3h of recovering data. Keep that in mind on scheduling the maintenance window.

after a few minutes:

% cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdb[4] sda[1] sdc[3]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [_UU]
      [>....................]  recovery =  4.8% (47825800/976631296) finish=158.3min speed=97781K/sec

unused devices: <none>

mdadm shows:

% mdadm --detail /dev/md0 

        Version : 1.2
  Creation Time : Wed Feb 26 21:00:17 2014
     Raid Level : raid5
     Array Size : 1953262592 (1862.78 GiB 2000.14 GB)
  Used Dev Size : 976631296 (931.39 GiB 1000.07 GB)
   Raid Devices : 3
  Total Devices : 3
    Persistence : Superblock is persistent

    Update Time : Mon Oct 17 21:52:05 2016
          State : clean, degraded, recovering
 Active Devices : 2
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 512K

 Rebuild Status : 58% complete

           Name : MyServer:0  (local to host MyServer)
           UUID : ef5da4df:3e53572e:c3fe1191:925b24cf
         Events : 554

    Number   Major   Minor   RaidDevice State
       1       8       16        1      active sync   /dev/sda
       4       8       32        0      spare rebuilding   /dev/sdb
       3       8       48        2      active sync   /dev/sdc

You can use watch command that refreshes every two seconds your terminal with the output :

# watch cat /proc/mdstat

Every 2.0s: cat /proc/mdstat                                                                                               Mon Oct 17 21:53:34 2016

Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdb[4] sda[1] sdc[3]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [_UU]
      [===========>.........]  recovery = 59.4% (580918844/976631296) finish=69.2min speed=95229K/sec

unused devices: <none>

Growing a Linux Raid

Even so … 2T is not a lot of disk usage these days! If you need to grow-extend your linux raid, then you need hard disks with the same geometry (or larger).

Steps on growing your linux raid are also simply:

# Umount the linux raid device:
% umount /dev/md0

# Add the new disk
% mdadm --add /dev/md0 /dev/sdd

# Check mdstat
% cat /proc/mdstat

# Grow linux raid by one device
%  mdadm --grow /dev/md0 --raid-devices=4

# watch mdstat for reshaping to complete - also 3h+ something
% watch cat /proc/mdstat

# Filesystem check your linux raid device
% fsck -y /dev/md0

# Resize - Important
% resize2fs /dev/md0

But sometimes life happens …

Need 1 spare to avoid degraded array, and only have 0.

mdadm: Need 1 spare to avoid degraded array, and only have 0.


mdadm: Failed to initiate reshape!

Sometimes you get an error that informs you that you can not grow your linux raid device! It’s not time to panic or flee the scene. You’ve got this. You have already kept a recent backup before you started and you also reading this blog post!

You need a (an extra) backup-file !

% mdadm --grow --raid-devices=4 --backup-file=/tmp/backup.file /dev/md0
mdadm: Need to backup 3072K of critical section..

% cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sda[4] sdb[0] sdd[3] sdc[1]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
      [>....................]  reshape =  0.0

% (66460/976631296) finish=1224.4min speed=13292K/sec

unused devices: <none>

1224.4min seems a lot !!!

dmesg shows:

% dmesg
[   36.477638] md: Autodetecting RAID arrays.
[   36.477649] md: Scanned 0 and added 0 devices.
[   36.477654] md: autorun ...
[   36.477658] md: ... autorun DONE.

[  602.987144] md: bind<sda>
[  603.219025] RAID conf printout:
[  603.219036]  --- level:5 rd:3 wd:3
[  603.219044]  disk 0, o:1, dev:sdb
[  603.219050]  disk 1, o:1, dev:sdc
[  603.219055]  disk 2, o:1, dev:sdd
[  608.650884] RAID conf printout:
[  608.650896]  --- level:5 rd:3 wd:3
[  608.650903]  disk 0, o:1, dev:sdb
[  608.650910]  disk 1, o:1, dev:sdc
[  608.650915]  disk 2, o:1, dev:sdd
[  684.308820] RAID conf printout:
[  684.308832]  --- level:5 rd:4 wd:4
[  684.308840]  disk 0, o:1, dev:sdb
[  684.308846]  disk 1, o:1, dev:sdc
[  684.308851]  disk 2, o:1, dev:sdd
[  684.308855]  disk 3, o:1, dev:sda
[  684.309079] md: reshape of RAID array md0
[  684.309089] md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
[  684.309094] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reshape.
[  684.309105] md: using 128k window, over a total of 976631296k.


% cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sda[4] sdb[0] sdd[3] sdc[1]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
      [>....................]  reshape =  0.0

% (349696/976631296) finish=697.9min speed=23313K/sec

unused devices: <none>

ok it’s now 670minutes

Time to use watch:

(after a while)

% watch cat /proc/mdstat

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sda[4] sdb[0] sdd[3] sdc[1]
      1953262592 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
      [===========>......]  reshape = 66.1% (646514752/976631296) finish=157.4min speed=60171K/sec

unused devices: <none>

mdadm shows:

% mdadm --detail /dev/md0

        Version : 1.2
  Creation Time : Thu Feb  6 13:06:34 2014
     Raid Level : raid5
     Array Size : 1953262592 (1862.78 GiB 2000.14 GB)
  Used Dev Size : 976631296 (931.39 GiB 1000.07 GB)
   Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Sat Oct 22 14:59:33 2016
          State : clean, reshaping
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

 Reshape Status : 66% complete
  Delta Devices : 1, (3->4)

           Name : MyServer:0
           UUID : d635095e:50457059:7e6ccdaf:7da91c9b
         Events : 1536

    Number   Major   Minor   RaidDevice State
       0       8       16        0      active sync   /dev/sdb
       1       8       32        1      active sync   /dev/sdc
       3       8       48        2      active sync   /dev/sdd
       4       8        0        3      active sync   /dev/sda

be patient and keep an aye on mdstat under proc.

So basically those are the steps, hopefuly you will find them useful.

Tag(s): md0, mdadm, linux, raid
Find your hard disk model

# /bin/find /sys/devices -type f -name model -exec cat {} \; 


# udisksctl status

MODEL                     REVISION  SERIAL               DEVICE
KINGSTON SV300S37A120G    527ABBF0  50026B774902D7E5     sda     
WDC WD10EURX-63FH1Y0      01.01A01  WD-WMC1U5525831      sdb     
WDC WD10EZRX-00A8LB0      01.01A01  WD-WCC1U2715714      sdc     
VB0250EAVER               HPG9      Z3TLRVYK             sdd     
VB0250EAVER               HPG9      Z3TLRRKM             sde   


sda   disk  111,8G KINGSTON SV300S3
sdb   disk  931,5G WDC WD10EURX-63F
sdc   disk  931,5G WDC WD10EZRX-00A
sdd   disk  232,9G VB0250EAVER     
sde   disk  232,9G VB0250EAVER     


# smartctl -a -i /dev/sda

# hdparm -i /dev/sda

# lshw -class disk

# hwinfo --disk

Tag(s): hard disk
JS get HTML code from a DIV element

Most people -reading this blog post- will scream in their chairs … PLZ keep in-mind that I am not a developer and perhaps the below workaround is just that, a workaround.

I have this case that I need to render (with JS) text that already has passed through the PHP parser.
The caveat is that the text output is inside a <DIV> element and has HTML code in it.

Most of you understand that HTML inside a DIV element is not something useful as the browser’s engine is rendering it to HTML on page load. That means, that we can not get the innerHTML of this DIV element, as it is already rendered by the browser.

Let me give you an example:


<!DOCTYPE html>
      <p align="center">
        <div> An Example </div>


If you open a test.html page with the above code, and fire up any browser, you will see only: An Example as the output of the above DIV. There is no way to get the HTML code from the above example.

You probably thinking that I need to edit the PHP parser. Actually this DIV element is been filled up with an Ajax request from the PHP API, so no luck on the server-side code.

After spending a brutal weekend with and reading through every stackoverflow question, nothing appeared to get me closer to my purpose.

I’ve tried jquery with .html(), .text(), getting the innerHTML, I’ve tried everything I could think of. The only way to get the HTML code from inside an HTML DOM element is if the HTML code was/is inside a TEXT element, somehow.

I needed to get a TEXT element instead of a DIV element, so that I could get the text value of the HTML element.

So here is my workaround:

I encapsulated a hidden textarea HTML element inside the DIV !

<div class="show_myclass">
<textarea class="myclass" style="display:none;">

<!DOCTYPE html>
      <p align="center">
        <div> An Example </div>

</ textarea>
</ div>

I can now, get the text value of the textarea and use it.
My JS code became something like this:

1.    $(".myclass").each(function(i, block ) {
2.        document.getElementsByClassName("show_myclass")[i].innerHTML = my_function_that_does_magic( block.value );
3.    });

Let me explain a few things … for people that are nοt so much familiar with jquery or JS (like me).

Line 1: Α jquery selector by class, exactly like this getElementsByClassName() in HTML DOM but it is an iterator already with each function. For every element with classname = myclass do something. In a page with multiple DIVs-TextAreas this will be very useful.

Line 2: Get the TEXT value from the textarea ( block.value ) and run it as argument thought our magic function. Then populate the HTML result on the DIV element with the same iterator.

In conclusion, when the browser finally renders the whole page, the above javascript code will override the DIV element and will instead of -not- showing the hidden textarea, will show the output of our my_function_that_does_magic function !!!

Tag(s): JS, javascript
Read It Later or Read It Never ?



I really like this comic.
I try to read/learn something every day.


Sometimes, when I find an interesting article, I like to mark it for reading it later.


I use many forms of marking, like pin tabs, bookmarking, sending url via email, save the html page to a folder, save it to my wallabag instance, leave my browser open to this tab, send the URL QR to my phone etc etc etc.


Are all the above ways productive?


None … the time to read something is now!
I mean the first time you lay your eyes upon the article.


Not later, not when you have free time, now.


That’s the way it works with me. Perhaps with you something else is more productive.


I have a short attention span and it is better for me to drop everything and read something carefully that save it for later or some other time.


When I really have to save it for later, my preferable way is to save it to my wallabag instance. It’s perfect and you will love it.


I also have a kobo ebook (e-ink) reader. Not the android based.
From my wallabag I can save them to epub and export them to my kobo.


But I am lazy and I never do it.


My kobo reader has a pocket (getpocket) account.


So I’ve tried to save some articles but not always pocket can parse properly the content of an article. Not even wallabag always work 100%.


The superiority of wallabag (and self-hosted application) is that when a parsing problem occurs I can fix them! Open a git push request and then EVERYBODY in the community will be able to read-this article from this content provider-later. I cant do something like that with pocket or readability.


And then … there are ads !!! Lots of ads, Tons of ads !!!


There is a correct way to do ads and this is when you are not covering the article you want people to read!
The are a lot of wrong ways to do ads: inline the text, above the article, hiding some of the content, make people buy a fee, provide an article to small pages (you know that height in HTML is not a problem, right?) and then there is bandwidth issues.

When I am on my mobile, I DONT want to pay extra for bandwidth I DIDNT ask and certainly do not care about it!!!
If I read the article on my tiny mobile display DO NOT COVER the article with huge ads that I can not find the X-close button because it doesnt fit to my display !!!

So yes, there is a correct way to do ads and that is by respecting the reader and there is a wrong way to do ads.


Getting back to the article’s subject, below you will see six (6) ways to read an article on my desktop. Of course there are hundreds ways but there are the most common ones:


Article: The cyberpunk dystopia we were warned about is already here

Extra info:
windows width: 852
2 times zoom-out to view more text

  1. Pocket
  2. Original Post in Firefox 48.0.1
  3. Wallabag
  4. Reader View in Firefox
  5. Chromium 52.0.2743.116
  6. Midori 0.5.11 - WebKitGTK+ 2.4.11

Click to zoom:

I believe that Reader View in Firefox is the winner of this test. It is clean and it is focusing on the actual article.
Impressive !

Tag(s): wallabag
Open compressed file with gzip zcat perl php lua python

I have a compressed file of:

250.000.000 lines
Compressed the file size is: 671M
Uncompressed, it's: 6,5G

Need to extract a plethora of things and verify some others.

I dont want to use bash but something more elegant, like python or lua.

Looking through “The-Internet”, I’ve created some examples for the single purpose of educating my self.

So here are my results.
BE AWARE they are far-far-far away from perfect in code or execution.

Sorted by (less) time of execution:


pigz - Parallel gzip - Zlib

# time pigz  -p4 -cd  2016-08-04-06.ldif.gz &> /dev/null 

real    0m9.980s
user    0m16.570s
sys 0m0.980s


gzip 1.8

# time /bin/gzip -cd 2016-08-04-06.ldif.gz &> /dev/null

real    0m23.951s
user    0m23.790s
sys 0m0.150s


zcat (gzip) 1.8

# time zcat 2016-08-04-06.ldif.gz &> /dev/null

real    0m24.202s
user    0m24.100s
sys 0m0.090s


Perl v5.24.0



open (FILE, '/bin/gzip -cd 2016-08-04-06.ldif.gz |');

while (my $line = ) {
  print $line;

close FILE;


# time ./ &> /dev/null

real    0m49.942s
user    1m14.260s
sys 0m2.350s


PHP 7.0.9 (cli)



< ? php

  $fp = gzopen("2016-08-04-06.ldif.gz", "r");

  while (($buffer = fgets($fp, 4096)) !== false) {
        echo $buffer;


 ? >


# time php -f dump.php &> /dev/null

real    1m19.407s
user    1m4.840s
sys 0m14.340s

PHP - Iteration #2

PHP 7.0.9 (cli)

Impressed with php results, I took the perl-approach on code:

< ? php

  $fp = popen("/bin/gzip -cd 2016-08-04-06.ldif.gz", "r");

  while (($buffer = fgets($fp, 4096)) !== false) {
        echo $buffer;


 ? >


# time php -f dump2.php &> /dev/null 

real    1m6.845s
user    1m15.590s
sys 0m19.940s

not bad !


Lua 5.3.3



local gzip = require 'gzip'

local filename = "2016-08-04-06.ldif.gz"

for l in gzip.lines(filename) do


# time ./dump.lua &> /dev/null

real    3m50.899s
user    3m35.080s
sys 0m15.780s

Lua - Iteration #2

Lua 5.3.3

I was depressed to see that php is faster than lua!!
Depressed I say !

So here is my next iteration on lua:



local file = assert(io.popen('/bin/gzip -cd 2016-08-04-06.ldif.gz', 'r'))

while true do
        line = file:read()
        if line == nil then break end
        print (line)


# time ./dump2.lua &> /dev/null 

real    2m45.908s
user    2m54.470s
sys 0m21.360s

One minute faster than before, but still too slow !!

Lua - Zlib

Lua 5.3.3

My next iteration with lua is using zlib :



local zlib = require 'zlib'
local filename = "2016-08-04-06.ldif.gz"

local block = 64
local d = zlib.inflate()

local file = assert(, "rb"))
while true do
  bytes = file:read(block)
  if not bytes then break end
  print (d(bytes))



# time ./dump.lua  &> /dev/null 

real    0m41.546s
user    0m40.460s
sys 0m1.080s

Now, that's what I am talking about !!!

Playing with window_size (block) can make your code faster or slower.

Python v3

Python 3.5.2



import gzip

with, 'r') as f:
    for line in f:


# time ./ &> /dev/null

real    13m14.460s
user    13m13.440s
sys 0m0.670s

Not enough tissues on the whole damn world!

Python v3 - Iteration #2

Python 3.5.2

but wait ... a moment ... The default mode for is 'rb'.
(read binary)

let's try this once more with rt(read-text) mode:



import gzip

with, 'rt') as f:
    for line in f:
        print(line, end="")


# time ./ &> /dev/null 

real    5m33.098s
user    5m32.610s
sys 0m0.410s

With only one super tiny change and run time in half!!!
But still tooo slow.

Python v3 - Iteration #3

Python 3.5.2

Let's try a third iteration with popen this time.



import os

cmd = "/bin/gzip -cd 2016-08-04-06.ldif.gz"
f = os.popen(cmd)
for line in f:
  print(line, end="")


# time ./ &> /dev/null 

real    6m45.646s
user    7m13.280s
sys 0m6.470s

Python v3 - zlib Iteration #1

Python 3.5.2

Let's try a zlib iteration this time.



import zlib

d = zlib.decompressobj(zlib.MAX_WBITS | 16)

with open(filename, 'rb') as f:
    for line in f:


# time ./ &> /dev/null 

real    1m4.389s
user    1m3.440s
sys 0m0.410s

finally some proper values with python !!!


All the running tests occurred to this machine:

4 x Intel(R) Core(TM) i3-3220 CPU @ 3.30GHz


Ok, I Know !

The shell-pipe approach of using gzip for opening the compressed file, is not fair to all the above code snippets.
But ... who cares ?

I need something that run fast as hell and does smart things on those data.

Get in touch

As I am not a developer, I know that you people know how to do these things even better!

So I would love to hear any suggestions or even criticism on the above examples.

I will update/report everything that will pass the "I think I know what this code do" rule and ... be gently with me ;)

PLZ use my email address: evaggelos [ _at_ ] balaskas [ _dot_ ] gr

to send me any suggestions

Thanks !

Tag(s): php, perl, python, lua, pigz
How to dockerize a live system

I need to run some ansible playbooks to a running (live) machine.
But, of-course, I cant use a production server for testing purposes !!

So here comes docker!
I have ssh access from my docker-server to this production server:

[docker-server] ssh livebox tar --one-file-system --sparse -C / -cf -  | docker import - centos6:livebox 

Then run the new docker image:

[docker-server]  docker run -t -i --rm -p 2222:22 centos6:livebox bash                                                  

[root@40b2bab2f306 /]# /usr/sbin/sshd -D                                                                             

Create a new entry on your hosts inventory file, that uses ssh port 2222
or create a new separated inventory file

and test it with ansible ping module:

# ansible -m ping -i hosts.docker dockerlivebox

dockerlivebox | success >> {
    "changed": false,
    "ping": "pong"

Tag(s): docker
Gaggia Classic - Graef CM 800


Tag(s): coffee
vagrant docker ansible

Recently, I had the opportunity to see a presentation on the subject by Alexandros Kosiaris.

I was never fan of vagrant (or even virtualbox) but I gave it a try and below are my personal notes on the matter.
All my notes are based on Archlinux as it is my primary distribution but I think you can try them with every Gnu Linux OS.


So what is Vagrant ?

Vagrant is a wrapper, an abstraction layer to deal with some virtual solutions, like virtualbox, Vmware, hyper-v, docker, aws etc etc etc
With a few lines you can describe what you want to do and then use vagrant to create your enviroment of virtual boxes to work with.

Just for the fun of it, I used docker


We first need to create and build a proper Docker Image!

The Dockerfile below, is suggesting that we already have an archlinux:latest docker image.
You can use your own dockerfile or docker image.

You need to have an ssh connection to this docker image and you will need -of course- to have a ssh password or a ssh authorized key built in this image for root. If you are using sudo (then even better) dont forget to add the user to sudoers!

# vim Dockerfile 

# sshd on archlinux
# VERSION               0.0.2

FROM     archlinux:latest
MAINTAINER  Evaggelos Balaskas < evaggelos _AT_ balaskas _DOT_ gr >

# Update the repositories
RUN  pacman -Syy && pacman -S --noconfirm openssh python2

# Generate host keys
RUN  /usr/bin/ssh-keygen -A

# Add password to root user
RUN  echo 'root:roottoor' | chpasswd

# Fix sshd
RUN  sed -i -e 's/^UsePAM yes/UsePAM no/g' /etc/ssh/sshd_config && echo 'PermitRootLogin yes' >> /etc/ssh/sshd_config

# Expose tcp port

# Run openssh daemon
CMD  ["/usr/sbin/sshd", "-D"]

Again, you dont need to follow this step by the book!
It is an example to understand that you need a proper docker image that you can ssh into it.

Build the docker image:

# docker build -t archlinux:sshd . 

On my PC:

# docker images 

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
archlinux           sshd                1b074ffe98be        7 days ago          636.2 MB
archlinux           latest              c0c56d24b865        7 days ago          534 MB
archlinux           devel               e66b5b8af509        2 weeks ago         607 MB
centos6             powerdns            daf76074f848        3 months ago        893 MB
centos6             newdnsps            642462a8dfb4        3 months ago        546.6 MB
centos7             cloudstack          b5e696e65c50        6 months ago        1.463 GB
centos7             latest              d96affc2f996        6 months ago        500.2 MB
centos6             latest              4ba27f5a1189        6 months ago        489.8 MB


We can define docker as our default provider with:


It is not necessary to define the default provider, as you will see below,
but it is also a good idea - if your forget to declare your vagrant provider later

Before we start with vagrant, let us create a new folder:

# mkdir -pv vagrant
# cd vagrant 


We are ready to initialized our enviroment for vagrant:

# vagrant init

A `Vagrantfile` has been placed in this directory. You are now
ready to `vagrant up` your first virtual environment! Please read
the comments in the Vagrantfile as well as documentation on
`` for more information on using Vagrant.

Initial Vagrantfile

A typical vagrant configuration file looks something like this:

# cat Vagrantfile
 cat Vagrantfile
# -*- mode: ruby -*-
# vi: set ft=ruby :

# All Vagrant configuration is done below. The "2" in Vagrant.configure
# configures the configuration version (we support older styles for
# backwards compatibility). Please don't change it unless you know what
# you're doing.
Vagrant.configure("2") do |config|
  # The most common configuration options are documented and commented below.
  # For a complete reference, please see the online documentation at

  # Every Vagrant development environment requires a box. You can search for
  # boxes at = "base"

  # Disable automatic box update checking. If you disable this, then
  # boxes will only be checked for updates when the user runs
  # `vagrant box outdated`. This is not recommended.
  # config.vm.box_check_update = false

  # Create a forwarded port mapping which allows access to a specific port
  # within the machine from a port on the host machine. In the example below,
  # accessing "localhost:8080" will access port 80 on the guest machine.
  # "forwarded_port", guest: 80, host: 8080

  # Create a private network, which allows host-only access to the machine
  # using a specific IP.
  # "private_network", ip: ""

  # Create a public network, which generally matched to bridged network.
  # Bridged networks make the machine appear as another physical device on
  # your network.
  # "public_network"

  # Share an additional folder to the guest VM. The first argument is
  # the path on the host to the actual folder. The second argument is
  # the path on the guest to mount the folder. And the optional third
  # argument is a set of non-required options.
  # config.vm.synced_folder "../data", "/vagrant_data"

  # Provider-specific configuration so you can fine-tune various
  # backing providers for Vagrant. These expose provider-specific options.
  # Example for VirtualBox:
  # config.vm.provider "virtualbox" do |vb|
  #   # Display the VirtualBox GUI when booting the machine
  #   vb.gui = true
  #   # Customize the amount of memory on the VM:
  #   vb.memory = "1024"
  # end
  # View the documentation for the provider you are using for more
  # information on available options.

  # Define a Vagrant Push strategy for pushing to Atlas. Other push strategies
  # such as FTP and Heroku are also available. See the documentation at
  # for more information.
  # config.push.define "atlas" do |push|
  # end

  # Enable provisioning with a shell script. Additional provisioners such as
  # Puppet, Chef, Ansible, Salt, and Docker are also available. Please see the
  # documentation for more information about their specific syntax and use.
  # config.vm.provision "shell", inline: <<-SHELL
  #   apt-get update
  #   apt-get install -y apache2

If you try to run this Vagrant configuration file with docker provider,
it will try to boot up base image (Vagrant Default box):

# vagrant up --provider=docker

Bringing machine 'default' up with 'docker' provider...
==> default: Box 'base' could not be found. Attempting to find and install...
    default: Box Provider: docker
    default: Box Version: >= 0
==> default: Box file was not detected as metadata. Adding it directly...
==> default: Adding box 'base' (v0) for provider: docker
    default: Downloading: base
An error occurred while downloading the remote file. The error
message, if any, is reproduced below. Please fix this error and try

Couldn't open file /ebal/Desktop/vagrant/base


Put the initial vagrantfile aside and create the below Vagrant configuration file:

Vagrant.configure("2") do |config|
  config.vm.provider "docker" do |d|
    d.image = "archlinux:sshd"

That translate to :

Vagrant Provider: docker
Docker Image: archlinux:sshd

Basic commands

Run vagrant to create our virtual box:

#  vagrant up

Bringing machine 'default' up with 'docker' provider...
==> default: Creating the container...
    default:   Name: vagrant_default_1466368592
    default:  Image: archlinux:sshd
    default: Volume: /home/ebal/Desktop/vagrant:/vagrant
    default: Container created: 4cf4649b47615469
==> default: Starting container...
==> default: Provisioners will not be run since container doesn't support SSH.

ok, we havent yet configured vagrant to use ssh

but we have a running docker instance:

# vagrant status

Current machine states:

default                   running (docker)

The container is created and running. You can stop it using
`vagrant halt`, see logs with `vagrant docker-logs`, and
kill/destroy it with `vagrant destroy`.

that we can verify with docker ps:

#  docker ps -a

CONTAINER ID        IMAGE               COMMAND               CREATED              STATUS              PORTS               NAMES
4cf4649b4761        archlinux:sshd      "/usr/sbin/sshd -D"   About a minute ago   Up About a minute   22/tcp              vagrant_default_1466368592


We need to destroy this instance:

#  vagrant destroy

    default: Are you sure you want to destroy the 'default' VM? [y/N] y
==> default: Stopping container...
==> default: Deleting the container...

Vagrant ssh

We need to edit Vagrantfile to add ssh support to our docker :

# vim Vagrantfile

Vagrant.configure("2") do |config|

    config.vm.provider "docker" do |d|
        d.image = "archlinux:sshd"
        d.has_ssh = true


and re-up our vagrant box:

#  vagrant up

Bringing machine 'default' up with 'docker' provider...
==> default: Creating the container...
    default:   Name: vagrant_default_1466368917
    default:  Image: archlinux:sshd
    default: Volume: /home/ebal/Desktop/vagrant:/vagrant
    default:   Port:
    default: Container created: b4fce563a9f9042c
==> default: Starting container...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address:
    default: SSH username: vagrant
    default: SSH auth method: private key
    default: Warning: Authentication failure. Retrying...
    default: Warning: Authentication failure. Retrying...

Vagrant will try to connect to our docker instance with the user: vagrant and a key.
But our docker image only have a root user and a root password !!

# vagrant status

Current machine states:

default                   running (docker)

The container is created and running. You can stop it using
`vagrant halt`, see logs with `vagrant docker-logs`, and
kill/destroy it with `vagrant destroy`.

#  vagrant destroy

    default: Are you sure you want to destroy the 'default' VM? [y/N] y
==> default: Stopping container...
==> default: Deleting the container...

Vagrant ssh - the Correct way !

We need to edit the Vagrantfile, properly:

# vim Vagrantfile

Vagrant.configure("2") do |config|

    config.ssh.username = 'root'
    config.ssh.password = 'roottoor'

    config.vm.provider "docker" do |d|
        d.image = "archlinux:sshd"
        d.has_ssh = true


# vagrant up

Bringing machine 'default' up with 'docker' provider...
==> default: Creating the container...
    default:   Name: vagrant_default_1466369126
    default:  Image: archlinux:sshd
    default: Volume: /home/ebal/Desktop/vagrant:/vagrant
    default:   Port:
    default: Container created: 7fef0efc8905bb3a
==> default: Starting container...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address:
    default: SSH username: root
    default: SSH auth method: password
    default: Warning: Connection refused. Retrying...
    default: Inserting generated public key within guest...
    default: Removing insecure key from the guest if it's present...
    default: Key inserted! Disconnecting and reconnecting using new SSH key...
==> default: Machine booted and ready!

# vagrant status

Current machine states:

default                   running (docker)

The container is created and running. You can stop it using
`vagrant halt`, see logs with `vagrant docker-logs`, and
kill/destroy it with `vagrant destroy`.

# vagrant ssh-config

Host default
  User root
  Port 22
  UserKnownHostsFile /dev/null
  StrictHostKeyChecking no
  PasswordAuthentication no
  IdentityFile /tmp/vagrant/.vagrant/machines/default/docker/private_key
  IdentitiesOnly yes
  LogLevel FATAL

# vagrant ssh

[root@7fef0efc8905 ~]# uptime
 20:45:48 up 11:33,  0 users,  load average: 0.53, 0.42, 0.28
[root@7fef0efc8905 ~]#
[root@7fef0efc8905 ~]#
[root@7fef0efc8905 ~]#
[root@7fef0efc8905 ~]# exit
Connection to closed.


It is time to add ansible to the mix!

Ansible Playbook

We need to create a basic ansible playbook:

# cat playbook.yml 

- hosts: all

      ansible_python_interpreter: "/usr/bin/env python2"

  gather_facts: no


    # Install package vim
    - pacman: name=vim state=present

The above playbook, is going to install vim, via pacman (archlinux PACkage MANager)!
Archlinux comes by default with python3 and with ansible_python_interpreter you are declaring to use python2!

Vagrantfile with Ansible

# cat Vagrantfile

Vagrant.configure("2") do |config|

    config.ssh.username = 'root'
    config.ssh.password = 'roottoor'

    config.vm.provider "docker" do |d|
        d.image = "archlinux:sshd"
        d.has_ssh = true

    config.vm.provision "ansible" do |ansible|
        ansible.verbose = "v"
        ansible.playbook = "playbook.yml"


Vagrant Docker Ansible

# vagrant up 

Bringing machine 'default' up with 'docker' provider...
==> default: Creating the container...
    default:   Name: vagrant_default_1466370194
    default:  Image: archlinux:sshd
    default: Volume: /home/ebal/Desktop/vagrant:/vagrant
    default:   Port:
    default: Container created: 8909eee7007b8d4f
==> default: Starting container...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address:
    default: SSH username: root
    default: SSH auth method: password
    default: Warning: Connection refused. Retrying...
    default: Inserting generated public key within guest...
    default: Removing insecure key from the guest if it's present...
    default: Key inserted! Disconnecting and reconnecting using new SSH key...
==> default: Machine booted and ready!

==> default: Running provisioner: ansible...
    default: Running ansible-playbook...
PYTHONUNBUFFERED=1 ANSIBLE_FORCE_COLOR=true ANSIBLE_HOST_KEY_CHECKING=false ANSIBLE_SSH_ARGS='-o UserKnownHostsFile=/dev/null -o IdentitiesOnly=yes -o ControlMaster=auto -o ControlPersist=60s' ansible-playbook --connection=ssh --timeout=30 --limit="default" --inventory-file=/mnt/VB0250EAVER/home/ebal/Desktop/vagrant/.vagrant/provisioners/ansible/inventory -v playbook.yml
Using /etc/ansible/ansible.cfg as config file

PLAY [all] *********************************************************************

TASK [pacman] ******************************************************************
changed: [default] => {"changed": true, "msg": "installed 1 package(s). "}

PLAY RECAP *********************************************************************
default                    : ok=1    changed=1    unreachable=0    failed=0   

# vagrant status

Current machine states:

default                   running (docker)

The container is created and running. You can stop it using
`vagrant halt`, see logs with `vagrant docker-logs`, and
kill/destroy it with `vagrant destroy`.

#  vagrant ssh 

[root@8909eee7007b ~]# vim --version
VIM - Vi IMproved 7.4 (2013 Aug 10, compiled Jun  9 2016 09:35:16)
Included patches: 1-1910
Compiled by Arch Linux

Vagrant Provisioning

The ansible-step is called: provisioning as you may already noticed.

If you make a few changes on this playbook, just type:

#  vagrant provision

and it will re-run the ansible part on this vagrant box !

Docker Notes

Personal Notes on this blog post.
[work in progress]

Why ?

Γιατί docker ?

To docker είναι ένα management εργαλείο για διαχείριση containers.
Εάν κι αρχικά βασίστηκε σε lxc, πλέον είναι αυτοτελές.

Containers είναι ένα isolated περιβάλλον, κάτι περισσότερο από
chroot(jail) κάτι λιγότερο από virtual machines.

Μπορούμε να σηκώσουμε αρκετά linux λειτουργικά, αλλά της ίδιας αρχιτεκτονικής.

Χρησιμοποιούνται κυρίως για development αλλά πλέον τρέχει μεγάλη
production υποδομή σε μεγάλα projects.

Κερδίζει γιατί το docker image που έχω στο PC μου, μπορεί να τρέξει αυτούσιο
σε οποιοδήποτε linux λειτουργικό (centos/fedora/debian/archlinux/whatever)
και προσφέρει isolation μεταξύ της εφαρμογής που τρέχει και του λειτουργικού.
Οι επιδόσεις -πλέον- είναι πολύ κοντά σε αυτές του συστήματος.

Σε production κυρίως χρησιμοποιείτε για continuous deployment,
καθώς τα images μπορεί να τα παράγουν developers, vendors ή whatever,
και θα παίξει σε commodity server με οποιοδήποτε λειτουργικό σύστημα!
Οπότε πλέον το “Σε εμένα παίζει” με το docker μεταφράζεται σε
“Και σε εμένα παίζει” !! στην παραγωγή.


Εάν δεν τρέχει το docker:

# systemctl restart docker

basic info on CentOS7 με devicemapper

# docker info

Containers: 0
Images: 4
Server Version: 1.9.1
Storage Driver: devicemapper
 Pool Name: docker-8:1-10617750-pool
 Pool Blocksize: 65.54 kB
 Base Device Size: 107.4 GB
 Backing Filesystem:
 Data file: /dev/loop0
 Metadata file: /dev/loop1
 Data Space Used: 1.654 GB
 Data Space Total: 107.4 GB
 Data Space Available: 105.7 GB
 Metadata Space Used: 1.642 MB
 Metadata Space Total: 2.147 GB
 Metadata Space Available: 2.146 GB
 Udev Sync Supported: true
 Deferred Removal Enabled: false
 Deferred Deletion Enabled: false
 Deferred Deleted Device Count: 0
 Data loop file: /var/lib/docker/devicemapper/devicemapper/data
 Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
 Library Version: 1.02.107-RHEL7 (2015-12-01)
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 3.10.0-327.13.1.el7.x86_64
Operating System: CentOS Linux 7 (Core)
CPUs: 16
Total Memory: 15.66 GiB
Name: myserverpc

basic info σε archlinux με btrfs :

# docker info
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 8
Server Version: 1.11.1
Storage Driver: btrfs
 Build Version: Btrfs v4.5.1
 Library Version: 101
Logging Driver: json-file
Cgroup Driver: cgroupfs
 Volume: local
 Network: null host bridge
Kernel Version: 4.4.11-1-lts
Operating System: Arch Linux
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 7.68 GiB
Name: myhomepc
Docker Root Dir:  /var/lib/docker/
Debug mode (client): false
Debug mode (server): false


# docker images -a

centos6     rpmbuild    ccb144691075  11 days ago       1.092 GB
< none >      < none >      6d8ff86f2749  11 days ago       1.092 GB
< none >      < none >      af92904a92b4  11 days ago       811.8 MB
< none >      < none >      8e429b38312b  11 days ago       392.7 MB

Τα none:none είναι built parent images που χρησιμοποιούνται από τα named docker images
αλλά δεν τα αποθηκεύσαμε σωστά.

Understanding Images

Ανάλογα με το back-end του docker, το docker κρατά σε delta-layers τις διαφορές
ανάμεσα στα parent/child docker images.

Αυτό μας διευκολύνει, γιατί μπορούμε στο production να έχουμε μεγάλες μήτρες από docker images
και να στέλνουμε μικρά delta-child docker images με το production service που θέλουμε να τρέξουμε.

Επίσης βοηθά και στο update.

Σε έξι μήνες, από την αρχική μας εικόνα, φτιάχνουμε το update image και πάνω σε αυτό
ξαναφορτώνουμε την εφαρμογή ή service που θέλουμε να τρέξει.

Έτσι μπορούμε να στέλνουμε μικρά σε μέγεθος docker images και να γίνονται build
τα διάφορα services μας πάνω σε αυτά.

Στο myserverpc μέσω του docker info είδαμε πως τρέχει σε:

Storage Driver: devicemapper

και χρησιμοποιεί το παρακάτω αρχείο για να κρατά τα images :

Data loop file: /var/lib/docker/devicemapper/devicemapper/data

Το οποίο στην πραγματικότητα είναι:

# file data
data: SGI XFS filesystem data (blksz 4096, inosz 256, v2 dirs)

Τα πιο δημοφιλή storage drivers είναι τα UFS & btrfs.
Προσωπικά (ebal) χρησιμοποιώ btrfs γιατί χρησιμοποιεί subvolumes
(σαν να λέμε ξεχωριστά cow volumes) για κάθε docker image
(parent ή child).

# ls /var/lib/docker/btrfs/subvolumes


Τι docker process τρέχουν:

# docker ps -a 

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

ενώ όταν τρέχει κάποιο:

CONTAINER ID  IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
62ef0ed8bc95  centos6:rpmbuild    "bash"              10 seconds ago      Up 9 seconds                            drunk_mietner

Δώστε σημασία στο NAMES

To docker δίνει randomly δύο ονόματα για ευκολότερη διαχείριση,
αλλιώς θα πρέπει να χρησιμοποιούμε το πλήρες hashed named.

Στο παραπάνω παράδειγμα:



Πως παίρνουμε πληροφορίες από ένα docker process:

# docker inspect drunk_mietner

    "Id": "62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f",
    "Created": "2016-06-05T07:41:18.821123985Z",
    "Path": "bash",
    "Args": [],
    "State": {
        "Status": "running",
        "Running": true,
        "Paused": false,
        "Restarting": false,
        "OOMKilled": false,
        "Dead": false,
        "Pid": 23664,
        "ExitCode": 0,
        "Error": "",
        "StartedAt": "2016-06-05T07:41:19.558616976Z",
        "FinishedAt": "0001-01-01T00:00:00Z"
    "Image": "ccb1446910754d6572976a6d36e5d0c8d1d029e4dc72133211670b28cf2f1d8f",
    "ResolvConfPath": "/var/lib/docker/containers/62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f/resolv.conf",
    "HostnamePath": "/var/lib/docker/containers/62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f/hostname",
    "HostsPath": "/var/lib/docker/containers/62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f/hosts",
    "LogPath": "/var/lib/docker/containers/62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f/62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f-json.log",
    "Name": "/drunk_mietner",
    "RestartCount": 0,
    "Driver": "devicemapper",
    "ExecDriver": "native-0.2",
    "MountLabel": "system_u:object_r:svirt_sandbox_file_t:s0:c344,c750",
    "ProcessLabel": "system_u:system_r:svirt_lxc_net_t:s0:c344,c750",
    "AppArmorProfile": "",
    "ExecIDs": null,
    "HostConfig": {
        "Binds": null,
        "ContainerIDFile": "",
        "LxcConf": [],
        "Memory": 0,
        "MemoryReservation": 0,
        "MemorySwap": 0,
        "KernelMemory": 0,
        "CpuShares": 0,
        "CpuPeriod": 0,
        "CpusetCpus": "",
        "CpusetMems": "",
        "CpuQuota": 0,
        "BlkioWeight": 0,
        "OomKillDisable": false,
        "MemorySwappiness": -1,
        "Privileged": false,
        "PortBindings": {},
        "Links": null,
        "PublishAllPorts": false,
        "Dns": [],
        "DnsOptions": [],
        "DnsSearch": [],
        "ExtraHosts": null,
        "VolumesFrom": null,
        "Devices": [],
        "NetworkMode": "default",
        "IpcMode": "",
        "PidMode": "",
        "UTSMode": "",
        "CapAdd": null,
        "CapDrop": null,
        "GroupAdd": null,
        "RestartPolicy": {
            "Name": "no",
            "MaximumRetryCount": 0
        "SecurityOpt": null,
        "ReadonlyRootfs": false,
        "Ulimits": null,
        "Sysctls": {},
        "LogConfig": {
            "Type": "json-file",
            "Config": {}
        "CgroupParent": "",
        "ConsoleSize": [
        "VolumeDriver": "",
        "ShmSize": 67108864
    "GraphDriver": {
        "Name": "devicemapper",
        "Data": {
            "DeviceId": "13",
            "DeviceName": "docker-8:1-10617750-62ef0ed8bc952d501f241dbc4ecda25d3a629880d27fbb7344b5429a44af985f",
            "DeviceSize": "107374182400"
    "Mounts": [],
    "Config": {
        "Hostname": "62ef0ed8bc95",
        "Domainname": "",
        "User": "",
        "AttachStdin": true,
        "AttachStdout": true,
        "AttachStderr": true,
        "Tty": true,
        "OpenStdin": true,
        "StdinOnce": true,
        "Env": null,
        "Cmd": [
        "Image": "centos6:rpmbuild",
        "Volumes": null,
        "WorkingDir": "",
        "Entrypoint": null,
        "OnBuild": null,
        "Labels": {},
        "StopSignal": "SIGTERM"
    "NetworkSettings": {
        "Bridge": "",
        "SandboxID": "992cf9db43c309484b8261904f46915a15eff3190026749841b93072847a14bc",
        "HairpinMode": false,
        "LinkLocalIPv6Address": "",
        "LinkLocalIPv6PrefixLen": 0,
        "Ports": {},
        "SandboxKey": "/var/run/docker/netns/992cf9db43c3",
        "SecondaryIPAddresses": null,
        "SecondaryIPv6Addresses": null,
        "EndpointID": "17b09b362d3b2be7d9c48377969049ac07cb821c482a9644970567fd5bb772f1",
        "Gateway": "",
        "GlobalIPv6Address": "",
        "GlobalIPv6PrefixLen": 0,
        "IPAddress": "",
        "IPPrefixLen": 16,
        "IPv6Gateway": "",
        "MacAddress": "02:42:ac:11:00:02",
        "Networks": {
            "bridge": {
                "EndpointID": "17b09b362d3b2be7d9c48377969049ac07cb821c482a9644970567fd5bb772f1",
                "Gateway": "",
                "IPAddress": "",
                "IPPrefixLen": 16,
                "IPv6Gateway": "",
                "GlobalIPv6Address": "",
                "GlobalIPv6PrefixLen": 0,
                "MacAddress": "02:42:ac:11:00:02"

output σε json, που σημαίνει εύκολο provisioning !!!


Ο πιο εύκολος τρόπος είναι να έχουμε ένα tar archive
από το σύστημα που θέλουμε και να το κάνουμε import:

# docker import - centos6:latest < a.tar


Πως σηκώνουμε ένα docker image:

# docker run -t -i --rm centos6:latest bash

Αυτό σημαίνει πως θα μας δώσει interactive process με entry-point το bash.
Τέλος, μόλις κλείσουμε το docker image θα εξαφανιστούν ΟΛΕΣ οι αλλαγές που έχουμε κάνει.

Χρειάζεται να τα διαγράφουμε, για να μην γεμίσουμε με images που έχουν μεταξύ τους μικρές αλλαγές

Μπορούμε να έχουμε docker processes χωρίς entry-point.

Αυτά είναι τα service oriented containers που το entry-point
είναι TCP port (συνήθως) και τρέχουν τα διάφορα services που θέλουμε.
Όλα αυτά αργότερα.


Μέσα σε ένα docker image:

[root@62ef0ed8bc95 /]# hostname

# ip a

1: lo:  mtu 65536 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever

11: eth0@if12:  mtu 1500 qdisc noqueue state UP
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:2/64 scope link
       valid_lft forever preferred_lft forever

# ip r

default via dev eth0 dev eth0  proto kernel  scope link  src 

private network 172.x.x.x

το οποίο έχει δημιουργηθεί από το myserverpc:

10: docker0:  mtu 1500 qdisc noqueue state UP
    link/ether 02:42:24:5c:42:f6 brd ff:ff:ff:ff:ff:ff
    inet scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:24ff:fe5c:42f6/64 scope link
       valid_lft forever preferred_lft forever

12: veth524ea1d@if11:  mtu 1500 qdisc noqueue master docker0 state UP
    link/ether 6e:39:ae:aa:ec:65 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 fe80::6c39:aeff:feaa:ec65/64 scope link
       valid_lft forever preferred_lft forever

# brctl show

bridge name bridge id       STP enabled interfaces
docker0     8000.0242245c42f6   no      veth524ea1d
virbr0      8000.525400990c9d   yes     virbr0-nic


ok, έχουμε κάνει τις αλλαγές μας ή έχουμε στήσει μια μήτρα ενός docker image
που θέλουμε να κρατήσουμε. Πως το κάνουμε commit ?

Από το myserverpc (κι όχι μέσα από το docker process):

# docker commit -p -m "centos6 rpmbuild test image" drunk_mietner centos6:rpmbuildtest

Το βλέπουμε πως έχει δημιουργηθεί:

# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
centos6             rpmbuildtest        95246c3b7b8b        3 seconds ago       1.092 GB
centos6             rpmbuild            ccb144691075        11 days ago         1.092 GB


και δεν το χρειαζόμαστε πλέον, θέλουμε να κρατήσουμε μόνο το centos6:rpmbuild

Εάν δεν έχει child docker images και δεν τρέχει κάποιο docker process βασισμένο σε αυτό το docker:

# docker rmi centos6:rpmbuildtest 

Untagged: centos6:rpmbuildtest
Deleted: 95246c3b7b8b77e9f5c70f2fd7b8ea2c8ec1f72e846897c87cd60722f6caabef

# docker images

centos6     rpmbuild    ccb144691075  11 days ago   1.092 GB
< none >      < none >      6d8ff86f2749  11 days ago   1.092 GB


οκ, έχουμε φτιάξει στον υπολογιστή μας το τέλειο docker image
και θέλουμε να το κάνουμε export για να το φορτώσουμε κάπου αλλού:

# docker export drunk_mietner > CentOS68_rpmbuild.tar

Tag(s): docker
wallabag upgrade notes 2.0.x

These are my personal notes on upgrading wallabag to it’s latest version (2.0.8):

Create a backup

# cd /var/www/html/
# mv wallabag wallabag_bak

Download latest version

# wget -c -qO - | tar -xz
# mv release-2.0.8 wallabag

Restore Settings

# cp -f wallabag_bak/app/config/parameters.yml wallabag/app/config/parameters.yml 
# rsync -r wallabag_bak/data/ wallabag/data/

[h3] Permissions [h3]

Don’t forget to fix the permissions on wallabag according to your web server settings:

# chown -R apache:apache wallabag

and …. that’s it !

Tag(s): wallabag
Lets Encrypt Client: certbot on Centos 6.8

Let’s Encrypt client: certbot is been written in python and as it’s predecessor needs at least Python 2.7.

But (still) in CentOS series 6 (currently 6.8) there is no natively support for python27.

So I did this thing below, quick & dirty:

# cd /usr/local/src/
# wget -c
# tar xf Python-2.7.11.tgz
# cd Python-2.7.11
# ./configure
# make
# make install

and these are my notes for renew certificates :

# ln -s /opt/Python-2.7/bin/python2.7 /usr/local/bin/python2

[root@1 certbot]# source venv/bin/activate
(venv)[root@1 certbot]#

# cd venv/bin/

# ./certbot renew --dry-run

# ./certbot renew

# rm /usr/local/bin/python2


Domain-based Message Authentication, Reporting and Conformance

What is dmarc in a nutshell:

An authentication Protocol that combines SPF & DKIM to reduce spoofed emails.
Depends on DNS so DANE would be great here!

notes on centos6:

You need to already have implemented SPF & DKIM

Outgoing Mail Servers


in your zone file, add something like this:

_dmarc    IN  TXT "v=DMARC1; p=none;"

increase the serial number of the zone and check it:

# dig +short txt
"v=DMARC1; p=none;"

dmarc tags

DMARC requires only two tags.

v: version
p: policy


Version is DMARC1 for the time being



We start from policy=none and trying to investigate mail logs


rua declares where the mail servers will send the reports regarding dmarc failures.

Incoming Mail Servers


# yum search opendmarc

# yum -y install opendmarc.x86_64

check process:

# netstat -ntlp|grep dmarc
tcp    0    0*    LISTEN    14538/opendmarc     


Add another milter:

# opendkim & opendmarc


# grep -Ev '#|^$' /etc/opendmarc.conf 

Socket inet:8893@localhost
SoftwareHeader true
SPFIgnoreResults true
SPFSelfValidate true
Syslog true
UMask 007
UserID opendmarc:mail

MilterDebug 1


# /etc/init.d/opendmarc restart

# chkconfig opendmarc on

DMARC Inspector


Tag(s): DMARC
Unknown User dovecot edition

The last couple months, I get over 400 unknown user errors on my imap (dovecot) server.

FYI this is the report:

dovecot: auth: ldap(aaaaaa, unknown user:
dovecot: auth: ldap(accountant, unknown user:
dovecot: auth: ldap(acosta, unknown user:
dovecot: auth: ldap(, unknown user:
dovecot: auth: ldap(adrian, unknown user:
dovecot: auth: ldap(alarm, unknown user:
dovecot: auth: ldap(alcala, unknown user:
dovecot: auth: ldap(alena, unknown user:
dovecot: auth: ldap(alfaro, unknown user:
dovecot: auth: ldap(alias, unknown user:
dovecot: auth: ldap(ally, unknown user:
dovecot: auth: ldap(almeida, unknown user:
dovecot: auth: ldap(alya, unknown user:
dovecot: auth: ldap(amara, unknown user:
dovecot: auth: ldap(amigo, unknown user:
dovecot: auth: ldap(amina, unknown user:
dovecot: auth: ldap(amity, unknown user:
dovecot: auth: ldap(analysis, unknown user:
dovecot: auth: ldap(analyst, unknown user:
dovecot: auth: ldap(anderson, unknown user:
dovecot: auth: ldap(andrade, unknown user:
dovecot: auth: ldap(andreea, unknown user:
dovecot: auth: ldap(andria, unknown user:
dovecot: auth: ldap(annalisa, unknown user:
dovecot: auth: ldap(annika, unknown user:
dovecot: auth: ldap(anon, unknown user:
dovecot: auth: ldap(anonymous, unknown user:
dovecot: auth: ldap(area, unknown user:
dovecot: auth: ldap(aris, unknown user:
dovecot: auth: ldap(arriaga, unknown user:
dovecot: auth: ldap(ashley, unknown user:
dovecot: auth: ldap(assistance, unknown user:
dovecot: auth: ldap(aya, unknown user:
dovecot: auth: ldap(azerty, unknown user:
dovecot: auth: ldap(baby, unknown user:
dovecot: auth: ldap(bad, unknown user:
dovecot: auth: ldap(ballesteros, unknown user:
dovecot: auth: ldap(banana, unknown user:
dovecot: auth: ldap(band, unknown user:
dovecot: auth: ldap(bank, unknown user:
dovecot: auth: ldap(barbara, unknown user:
dovecot: auth: ldap(barcode, unknown user:
dovecot: auth: ldap(barney, unknown user:
dovecot: auth: ldap(barrie, unknown user:
dovecot: auth: ldap(basil, unknown user:
dovecot: auth: ldap(bob, unknown user:
dovecot: auth: ldap(camp, unknown user:
dovecot: auth: ldap(campos, unknown user:
dovecot: auth: ldap(candi, unknown user:
dovecot: auth: ldap(carlo, unknown user:
dovecot: auth: ldap(carolina, unknown user:
dovecot: auth: ldap(cashier, unknown user:
dovecot: auth: ldap(casper, unknown user:
dovecot: auth: ldap(chad, unknown user:
dovecot: auth: ldap(challenge, unknown user:
dovecot: auth: ldap(chantal, unknown user:
dovecot: auth: ldap(charly, unknown user:
dovecot: auth: ldap(cher, unknown user:
dovecot: auth: ldap(cheryl, unknown user:
dovecot: auth: ldap(clare, unknown user:
dovecot: auth: ldap(classic, unknown user:
dovecot: auth: ldap(claudia, unknown user:
dovecot: auth: ldap(clock, unknown user:
dovecot: auth: ldap(consola, unknown user:
dovecot: auth: ldap(contactus, unknown user:
dovecot: auth: ldap(contract, unknown user:
dovecot: auth: ldap(craig, unknown user:
dovecot: auth: ldap(cuenta, unknown user:
dovecot: auth: ldap(cuentas, unknown user:
dovecot: auth: ldap(culture, unknown user:
dovecot: auth: ldap(dale, unknown user:
dovecot: auth: ldap(danielle, unknown user:
dovecot: auth: ldap(dante, unknown user:
dovecot: auth: ldap(davis, unknown user:
dovecot: auth: ldap(day, unknown user:
dovecot: auth: ldap(denis, unknown user:
dovecot: auth: ldap(dentrix, unknown user:
dovecot: auth: ldap(deposit, unknown user:
dovecot: auth: ldap(designer, unknown user:
dovecot: auth: ldap(desmond, unknown user:
dovecot: auth: ldap(devel, unknown user:
dovecot: auth: ldap(device, unknown user:
dovecot: auth: ldap(devin, unknown user:
dovecot: auth: ldap(diamante, unknown user:
dovecot: auth: ldap(digital, unknown user:
dovecot: auth: ldap(dimas, unknown user:
dovecot: auth: ldap(direktor, unknown user:
dovecot: auth: ldap(discount, unknown user:
dovecot: auth: ldap(discussion, unknown user:
dovecot: auth: ldap(disk, unknown user:
dovecot: auth: ldap(display, unknown user:
dovecot: auth: ldap(doctor, unknown user:
dovecot: auth: ldap(document, unknown user:
dovecot: auth: ldap(dolores, unknown user:
dovecot: auth: ldap(domingo, unknown user:
dovecot: auth: ldap(dominio, unknown user:
dovecot: auth: ldap(donald, unknown user:
dovecot: auth: ldap(donna, unknown user:
dovecot: auth: ldap(dorado, unknown user:
dovecot: auth: ldap(doreen, unknown user:
dovecot: auth: ldap(doris, unknown user:
dovecot: auth: ldap(dot, unknown user:
dovecot: auth: ldap(dovecot, unknown user:
dovecot: auth: ldap(draft, unknown user:
dovecot: auth: ldap(dragon, unknown user:
dovecot: auth: ldap(drama, unknown user:
dovecot: auth: ldap(drawing, unknown user:
dovecot: auth: ldap(dream, unknown user:
dovecot: auth: ldap(dundee, unknown user:
dovecot: auth: ldap(eagle, unknown user:
dovecot: auth: ldap(ear, unknown user:
dovecot: auth: ldap(easy, unknown user:
dovecot: auth: ldap(econom, unknown user:
dovecot: auth: ldap(eddy, unknown user:
dovecot: auth: ldap(edita, unknown user:
dovecot: auth: ldap(edu, unknown user:
dovecot: auth: ldap(education, unknown user:
dovecot: auth: ldap(eldon, unknown user:
dovecot: auth: ldap(elfa, unknown user:
dovecot: auth: ldap(eliza, unknown user:
dovecot: auth: ldap(elizabeth, unknown user:
dovecot: auth: ldap(ellen, unknown user:
dovecot: auth: ldap(elsie, unknown user:
dovecot: auth: ldap(elvin, unknown user:
dovecot: auth: ldap(emmanuel, unknown user:
dovecot: auth: ldap(empleos, unknown user:
dovecot: auth: ldap(enrique, unknown user:
dovecot: auth: ldap(envio, unknown user:
dovecot: auth: ldap(erin, unknown user:
dovecot: auth: ldap(estel, unknown user:
dovecot: auth: ldap(, unknown user:
dovecot: auth: ldap(felipe, unknown user:
dovecot: auth: ldap(fischer, unknown user:
dovecot: auth: ldap(florence, unknown user:
dovecot: auth: ldap(forum, unknown user:
dovecot: auth: ldap(fred, unknown user:
dovecot: auth: ldap(giuseppe, unknown user:
dovecot: auth: ldap(golden, unknown user:
dovecot: auth: ldap(hannah, unknown user:
dovecot: auth: ldap(henry, unknown user:
dovecot: auth: ldap(home, unknown user:
dovecot: auth: ldap(howard, unknown user:
dovecot: auth: ldap(hudson, unknown user:
dovecot: auth: ldap(ian, unknown user:
dovecot: auth: ldap(, unknown user:
dovecot: auth: ldap(ingrid, unknown user:
dovecot: auth: ldap(inspector, unknown user:
dovecot: auth: ldap(installer, unknown user:
dovecot: auth: ldap(invite, unknown user:
dovecot: auth: ldap(irena, unknown user:
dovecot: auth: ldap(irene, unknown user:
dovecot: auth: ldap(isabel, unknown user:
dovecot: auth: ldap(ivan, unknown user:
dovecot: auth: ldap(jackie, unknown user:
dovecot: auth: ldap(jaime, unknown user:
dovecot: auth: ldap(jane, unknown user:
dovecot: auth: ldap(jerry, unknown user:
dovecot: auth: ldap(jo, unknown user:
dovecot: auth: ldap(joanna, unknown user:
dovecot: auth: ldap(joaquin, unknown user:
dovecot: auth: ldap(job, unknown user:
dovecot: auth: ldap(joline, unknown user:
dovecot: auth: ldap(jon, unknown user:
dovecot: auth: ldap(jose, unknown user:
dovecot: auth: ldap(joy, unknown user:
dovecot: auth: ldap(js, unknown user:
dovecot: auth: ldap(juanita, unknown user:
dovecot: auth: ldap(jule, unknown user:
dovecot: auth: ldap(julian, unknown user:
dovecot: auth: ldap(julieta, unknown user:
dovecot: auth: ldap(justin, unknown user:
dovecot: auth: ldap(kai, unknown user:
dovecot: auth: ldap(karan, unknown user:
dovecot: auth: ldap(karina, unknown user:
dovecot: auth: ldap(kathy, unknown user:
dovecot: auth: ldap(keith, unknown user:
dovecot: auth: ldap(keller, unknown user:
dovecot: auth: ldap(kelvin, unknown user:
dovecot: auth: ldap(kennedy, unknown user:
dovecot: auth: ldap(kernel, unknown user:
dovecot: auth: ldap(kid, unknown user:
dovecot: auth: ldap(kiki, unknown user:
dovecot: auth: ldap(kim, unknown user:
dovecot: auth: ldap(kimberley, unknown user:
dovecot: auth: ldap(kind, unknown user:
dovecot: auth: ldap(king, unknown user:
dovecot: auth: ldap(kiosk, unknown user:
dovecot: auth: ldap(kip, unknown user:
dovecot: auth: ldap(kira, unknown user:
dovecot: auth: ldap(kirk, unknown user:
dovecot: auth: ldap(kirsten, unknown user:
dovecot: auth: ldap(kitty, unknown user:
dovecot: auth: ldap(knife, unknown user:
dovecot: auth: ldap(koko, unknown user:
dovecot: auth: ldap(kraft, unknown user:
dovecot: auth: ldap(kris, unknown user:
dovecot: auth: ldap(kym, unknown user:
dovecot: auth: ldap(kyra, unknown user:
dovecot: auth: ldap(lane, unknown user:
dovecot: auth: ldap(language, unknown user:
dovecot: auth: ldap(larkin, unknown user:
dovecot: auth: ldap(laurie, unknown user:
dovecot: auth: ldap(leadership, unknown user:
dovecot: auth: ldap(lenny, unknown user:
dovecot: auth: ldap(lenovo, unknown user:
dovecot: auth: ldap(leslie, unknown user:
dovecot: auth: ldap(level, unknown user:
dovecot: auth: ldap(levi, unknown user:
dovecot: auth: ldap(libby, unknown user:
dovecot: auth: ldap(liliana, unknown user:
dovecot: auth: ldap(lina, unknown user:
dovecot: auth: ldap(linda, unknown user:
dovecot: auth: ldap(lisette, unknown user:
dovecot: auth: ldap(local, unknown user:
dovecot: auth: ldap(log, unknown user:
dovecot: auth: ldap(logs, unknown user:
dovecot: auth: ldap(lori, unknown user:
dovecot: auth: ldap(louis, unknown user:
dovecot: auth: ldap(luciano, unknown user:
dovecot: auth: ldap(magdalena, unknown user:
dovecot: auth: ldap(maggie, unknown user:
dovecot: auth: ldap(main, unknown user:
dovecot: auth: ldap(maint, unknown user:
dovecot: auth: ldap(management, unknown user:
dovecot: auth: ldap(manolo, unknown user:
dovecot: auth: ldap(manzanares, unknown user:
dovecot: auth: ldap(marcos, unknown user:
dovecot: auth: ldap(mariana, unknown user:
dovecot: auth: ldap(marion, unknown user:
dovecot: auth: ldap(marisa, unknown user:
dovecot: auth: ldap(marna, unknown user:
dovecot: auth: ldap(martina, unknown user:
dovecot: auth: ldap(mat, unknown user:
dovecot: auth: ldap(matt, unknown user:
dovecot: auth: ldap(mauricio, unknown user:
dovecot: auth: ldap(mauro, unknown user:
dovecot: auth: ldap(max, unknown user:
dovecot: auth: ldap(maximo, unknown user:
dovecot: auth: ldap(may, unknown user:
dovecot: auth: ldap(mendoza, unknown user:
dovecot: auth: ldap(mercadeo, unknown user:
dovecot: auth: ldap(mercado, unknown user:
dovecot: auth: ldap(meridian, unknown user:
dovecot: auth: ldap(message, unknown user:
dovecot: auth: ldap(mexico, unknown user:
dovecot: auth: ldap(michelle, unknown user:
dovecot: auth: ldap(miguel, unknown user:
dovecot: auth: ldap(mimi, unknown user:
dovecot: auth: ldap(mirella, unknown user:
dovecot: auth: ldap(modem, unknown user:
dovecot: auth: ldap(montero, unknown user:
dovecot: auth: ldap(morales, unknown user:
dovecot: auth: ldap(moreno, unknown user:
dovecot: auth: ldap(muriel, unknown user:
dovecot: auth: ldap(mysql, unknown user:
dovecot: auth: ldap(nadia, unknown user:
dovecot: auth: ldap(nandi, unknown user:
dovecot: auth: ldap(naranjo, unknown user:
dovecot: auth: ldap(nathalie, unknown user:
dovecot: auth: ldap(nathan, unknown user:
dovecot: auth: ldap(nava, unknown user:
dovecot: auth: ldap(neil, unknown user:
dovecot: auth: ldap(neptune, unknown user:
dovecot: auth: ldap(network, unknown user:
dovecot: auth: ldap(new, unknown user:
dovecot: auth: ldap(newton, unknown user:
dovecot: auth: ldap(nicholas, unknown user:
dovecot: auth: ldap(nichole, unknown user:
dovecot: auth: ldap(nicole, unknown user:
dovecot: auth: ldap(nikki, unknown user:
dovecot: auth: ldap(nina, unknown user:
dovecot: auth: ldap(noc, unknown user:
dovecot: auth: ldap(norma, unknown user:
dovecot: auth: ldap(norton, unknown user:
dovecot: auth: ldap(oleg, unknown user:
dovecot: auth: ldap(orlando, unknown user:
dovecot: auth: ldap(pablo, unknown user:
dovecot: auth: ldap(paige, unknown user:
dovecot: auth: ldap(paolo, unknown user:
dovecot: auth: ldap(password, unknown user:
dovecot: auth: ldap(pat, unknown user:
dovecot: auth: ldap(patricia, unknown user:
dovecot: auth: ldap(patty, unknown user:
dovecot: auth: ldap(payment, unknown user:
dovecot: auth: ldap(paz, unknown user:
dovecot: auth: ldap(pc03, unknown user:
dovecot: auth: ldap(pereira, unknown user:
dovecot: auth: ldap(perfil, unknown user:
dovecot: auth: ldap(perl, unknown user:
dovecot: auth: ldap(perry, unknown user:
dovecot: auth: ldap(pharmacy, unknown user:
dovecot: auth: ldap(philip, unknown user:
dovecot: auth: ldap(phoenix, unknown user:
dovecot: auth: ldap(physics, unknown user:
dovecot: auth: ldap(pics, unknown user:
dovecot: auth: ldap(pie, unknown user:
dovecot: auth: ldap(pina, unknown user:
dovecot: auth: ldap(place, unknown user:
dovecot: auth: ldap(plant, unknown user:
dovecot: auth: ldap(point, unknown user:
dovecot: auth: ldap(police, unknown user:
dovecot: auth: ldap(politics, unknown user:
dovecot: auth: ldap(polly, unknown user:
dovecot: auth: ldap(pool, unknown user:
dovecot: auth: ldap(pop3, unknown user:
dovecot: auth: ldap(portatil, unknown user:
dovecot: auth: ldap(poster, unknown user:
dovecot: auth: ldap(pot, unknown user:
dovecot: auth: ldap(potato, unknown user:
dovecot: auth: ldap(power, unknown user:
dovecot: auth: ldap(practice, unknown user:
dovecot: auth: ldap(praise, unknown user:
dovecot: auth: ldap(president, unknown user:
dovecot: auth: ldap(prince, unknown user:
dovecot: auth: ldap(priority, unknown user:
dovecot: auth: ldap(process, unknown user:
dovecot: auth: ldap(profesor, unknown user:
dovecot: auth: ldap(professional, unknown user:
dovecot: auth: ldap(professor, unknown user:
dovecot: auth: ldap(profile, unknown user:
dovecot: auth: ldap(promise, unknown user:
dovecot: auth: ldap(protocol, unknown user:
dovecot: auth: ldap(proyecto, unknown user:
dovecot: auth: ldap(ps, unknown user:
dovecot: auth: ldap(puertas, unknown user:
dovecot: auth: ldap(python, unknown user:
dovecot: auth: ldap(qtss, unknown user:
dovecot: auth: ldap(rabia, unknown user:
dovecot: auth: ldap(rack, unknown user:
dovecot: auth: ldap(rae, unknown user:
dovecot: auth: ldap(ralph, unknown user:
dovecot: auth: ldap(ram, unknown user:
dovecot: auth: ldap(ramiro, unknown user:
dovecot: auth: ldap(raquel, unknown user:
dovecot: auth: ldap(ray, unknown user:
dovecot: auth: ldap(read, unknown user:
dovecot: auth: ldap(reality, unknown user:
dovecot: auth: ldap(rebecca, unknown user:
dovecot: auth: ldap(rechnung, unknown user:
dovecot: auth: ldap(recording, unknown user:
dovecot: auth: ldap(recover, unknown user:
dovecot: auth: ldap(red, unknown user:
dovecot: auth: ldap(reed, unknown user:
dovecot: auth: ldap(reference, unknown user:
dovecot: auth: ldap(register, unknown user:
dovecot: auth: ldap(registro, unknown user:
dovecot: auth: ldap(remoto, unknown user:
dovecot: auth: ldap(ricky, unknown user:
dovecot: auth: ldap(robin, unknown user:
dovecot: auth: ldap(rocio, unknown user:
dovecot: auth: ldap(roger, unknown user:
dovecot: auth: ldap(roman, unknown user:
dovecot: auth: ldap(rosario, unknown user:
dovecot: auth: ldap(ruben, unknown user:
dovecot: auth: ldap(sales1, unknown user:
dovecot: auth: ldap(sally, unknown user:
dovecot: auth: ldap(sam, unknown user:
dovecot: auth: ldap(samantha, unknown user:
dovecot: auth: ldap(sandi, unknown user:
dovecot: auth: ldap(sandra, unknown user:
dovecot: auth: ldap(sandy, unknown user:
dovecot: auth: ldap(sarah, unknown user:
dovecot: auth: ldap(schmidt, unknown user:
dovecot: auth: ldap(sean, unknown user:
dovecot: auth: ldap(sensor, unknown user:
dovecot: auth: ldap(seo, unknown user:
dovecot: auth: ldap(share, unknown user:
dovecot: auth: ldap(sharon, unknown user:
dovecot: auth: ldap(ship, unknown user:
dovecot: auth: ldap(simon, unknown user:
dovecot: auth: ldap(smile, unknown user:
dovecot: auth: ldap(spam, unknown user:
dovecot: auth: ldap(, unknown user:
dovecot: auth: ldap(spectrum, unknown user:
dovecot: auth: ldap(sql, unknown user:
dovecot: auth: ldap(sqlservice, unknown user:
dovecot: auth: ldap(staging, unknown user:
dovecot: auth: ldap(standard, unknown user:
dovecot: auth: ldap(studio, unknown user:
dovecot: auth: ldap(summer, unknown user:
dovecot: auth: ldap(sunny, unknown user:
dovecot: auth: ldap(sync, unknown user:
dovecot: auth: ldap(tania, unknown user:
dovecot: auth: ldap(tatiana, unknown user:
dovecot: auth: ldap(tax, unknown user:
dovecot: auth: ldap(telecomunicaciones, unknown user:
dovecot: auth: ldap(, unknown user:
dovecot: auth: ldap(testpc, unknown user:
dovecot: auth: ldap(tools, unknown user:
dovecot: auth: ldap(touch, unknown user:
dovecot: auth: ldap(tower, unknown user:
dovecot: auth: ldap(traci, unknown user:
dovecot: auth: ldap(tracy, unknown user:
dovecot: auth: ldap(trade, unknown user:
dovecot: auth: ldap(traffic, unknown user:
dovecot: auth: ldap(train, unknown user:
dovecot: auth: ldap(treasure, unknown user:
dovecot: auth: ldap(tristan, unknown user:
dovecot: auth: ldap(troy, unknown user:
dovecot: auth: ldap(trujillo, unknown user:
dovecot: auth: ldap(truman, unknown user:
dovecot: auth: ldap(ts, unknown user:
dovecot: auth: ldap(tucker, unknown user:
dovecot: auth: ldap(tyler, unknown user:
dovecot: auth: ldap(type, unknown user:
dovecot: auth: ldap(ubuntu, unknown user:
dovecot: auth: ldap(unicorn, unknown user:
dovecot: auth: ldap(union, unknown user:
dovecot: auth: ldap(upgrade, unknown user:
dovecot: auth: ldap(usuarioprueba, unknown user:
dovecot: auth: ldap(uucp, unknown user:
dovecot: auth: ldap(val, unknown user:
dovecot: auth: ldap(valenzuela, unknown user:
dovecot: auth: ldap(valeria, unknown user:
dovecot: auth: ldap(valerie, unknown user:
dovecot: auth: ldap(valerio, unknown user:
dovecot: auth: ldap(value, unknown user:
dovecot: auth: ldap(vanessa, unknown user:
dovecot: auth: ldap(vector, unknown user:
dovecot: auth: ldap(venta, unknown user:
dovecot: auth: ldap(ventas2, unknown user:
dovecot: auth: ldap(vente, unknown user:
dovecot: auth: ldap(verhaal, unknown user:
dovecot: auth: ldap(veronique, unknown user:
dovecot: auth: ldap(vincenzo, unknown user:
dovecot: auth: ldap(virgil, unknown user:
dovecot: auth: ldap(vnc, unknown user:
dovecot: auth: ldap(voice, unknown user:
dovecot: auth: ldap(wall, unknown user:
dovecot: auth: ldap(walter, unknown user:
dovecot: auth: ldap(watch, unknown user:
dovecot: auth: ldap(water, unknown user:
dovecot: auth: ldap(wave, unknown user:
dovecot: auth: ldap(webmaster, unknown user:
dovecot: auth: ldap(, unknown user:
dovecot: auth: ldap(william, unknown user:
dovecot: auth: ldap(x, unknown user:
Tag(s): dovecot
Use a different email address for every online account

Reading through “Smart Girl’s Guide to Privacy - Practical Tips for Staying Safe Online by Violet Blue” (totally recommend it), there is a great tip in the first few pages:

- Use different email addresses for different online accounts.

… but is it possible ?

Different Passwords

We already know that we need to use a different password for every site. So we use lastpass or password managers for keeping our different passwords safe. We are nowadays used to create/generate complex passwords for every site, but is it absolutely necessary to also have a different email address for every single one ?

Different Email Addresses

Let me be as clear as I can: There is no obvious answer.

If you value your online privacy and your security threat model is set really high, then Yes you also need a different email address.

But it depends entirely on you and how you use your online identity. Perhaps in social media sites (like facebook or twitter) you dont need to give your personal email address, but perhaps on linkedin you want to use your well-known email-identity. So again, it depends on your security thread model.

Another crucial tip: DO NOT cross-connect your online personas from different social medias.

Disposable Email Server

In this blog post, I will try to describe the simple steps you need to take, to create your own personal disposable email server. In simple words, that means that you can dynamically create and use a unique/specific-site-only email address that you can use for sign-up or register to a new site. Using a different email address & a different passwords for every site online, you are making it really difficult for someone to hack you.

Even if someone can get access to this specific website or -somehow- can retrieve your online account (sites are been hacked every day), you are sure that none of your other online accounts/identities can not be accessed too.


To do that you will need a disposable domain. It does not have to be something clever or even useful. It needs to be something easy to write & remember. In my opinion, just get a cheap domain. If your registar support WHOIS Privacy, then even better. If dont, then try to find a registar that supports WHOIS Privacy but it isnt a blocking issue.

For this blog post I will use:


In theory, we will create a “catch-all” domain/mail server, that will catch and forward all these emails to our current/primary email address.


So nice, you have a disposable domain. What next ?

You need to setup a new domain dns zone for your disposable domain.
And then add a MX record, like the notes below:    86400   IN  MX  0   86400   IN  A

replace with the server’s IP !!

Mail Server

Just install postfix !

My “notable” settings are these below:

# postconf -n

inet_interfaces = all
inet_protocols = all

message_size_limit = 35651584

smtp_address_preference = ipv6

smtpd_banner = The sky above the port was the color of television, tuned to a dead channel

virtual_alias_domains =
virtual_alias_maps = hash:/etc/postfix/virtual

In my /etc/postfix/virtual I have these lines:

(dont forget to postmap and reload)

# postmap /etc/postfix/virtual 

# postfix reload

…. and …. that is it, actually !!!

a. Be aware the my disposable email server is dual stack.

b. If you need to create an emailing list, try something like this: ,

dont forget to:

# postmap /etc/postfix/virtual

and reload postfix:

# postfix reload

How to use it

From now on, whenever you need to type an email address somewhere, just type a new (random or not) email address with this new disposable domain.

The catch-all setting will FWD any email to your primary email address.

I like to use the below specific pattern: When you need to sign-up to a new site, use the sites url as your new email address.


It’s now obvious that next time you get SPAM, you will know which one to blame (I am not suggesting that twitter is sending spam, it is just an example!).

You can also change your email address from all the sites that you have already subscribe (github, mailing lists, etc etc).

Hope this post has been helpful and easy enough for everyone.

FreshRSS Installation HowTo

Google Reader was -of general acceptance- the best RSS feed reader.
Yahoo had it’s own “perfect” project to parse feeds: Yahoo! Pipes


What did both projects have in common?

They both were cloud projects
that are now discontinued
cause their companies could not profit from them !!!


So a lot of people started to look up on self-hosted RSS readers to overcome this issue.
Below are my notes on FreshRSS , a free, self-hostable aggregator…


First, download the latest version of FreshRSS:




Download and Setup

# wget -c

# unzip 

# mv FreshRSS-master/ FreshRSS

# chown -R apache:apache FreshRSS


Create a new Virtual Host on apache and use Let’s Encrypt to create a new SSL certificate:

< VirtualHost *:443 >


    # SSL Support
    SSLEngine on

    SSLProtocol ALL -SSLv2 -SSLv3
    SSLHonorCipherOrder on
    SSLCipherSuite HIGH:!aNULL:!MD5

    SSLCertificateFile /etc/letsencrypt/live/
    SSLCertificateKeyFile /etc/letsencrypt/live/
    SSLCertificateChainFile /etc/letsencrypt/live/

    # Logs
    CustomLog logs/FreshRSS.access.log combined
    ErrorLog  logs/FreshRSS.error.log

    DocumentRoot /var/www/html/FreshRSS/

    < Directory /var/www/html/FreshRSS/ >
            Order allow,deny
            Allow from all
    < /Directory >

< /VirtualHost >

reload your apache and after that, open your browser to begin the installation process.











SQLite Backend


I prefer to use SQLite for my backend self-hosted projects, cause the backup process is a lot easier than with mysql.






At this point you have a fresh FreshRSS installation (self-hosted) on your server!
If you just want to use it through your browser, you are done.




If you already have a OPML (Outline Processor Markup Language) file with your rss/atom feeds, then you can upload it (import) through the Subscription Manager:




Feeds - Automated Updates

So conclude our FreshRSS setup, we need to automate the update of our feeds. To do that, we just need to add a cron script.

# vim /etc/crontab

*/15 * * * * apache /usr/bin/php /var/www/html/FreshRSS//app/actualize_script.php &> /tmp/fresh.log



What about your android device (smart phone or tablet) ?

You can use EasyRSS !
Just install it from Fdroid and run it:




FreshRSS - API


To use EasyRSS with FreshRSS, you need to enable the API support from FreshRSS.
The EasyRSS then, will use the api through a token, so to keep things simple enough, we will also change our password to the token ID.

So go to Settings —> Authentication and enable:

    Allow API access (required for mobile apps)




Then go to Settings –> Profile and change your password too:




After that, you can now type your settings on your EasyRSS app:








Tag(s): FreshRSS, EasyRSS
Let’s Encrypt on Prosody & enable Forward secrecy

Below is my setup to enable Forward secrecy

Generate DH parameters:

# openssl dhparam -out /etc/pki/tls/dh-2048.pem 2048

and then configure your prosody with Let’s Encrypt certificates

VirtualHost ""

  ssl = {
      key = "/etc/letsencrypt/live/";
      certificate = "/etc/letsencrypt/live/";
      cafile = "/etc/pki/tls/certs/ca-bundle.crt";

      # enable strong encryption
      dhparam = "/etc/pki/tls/dh-2048.pem";

if you only want to accept TLS connection from clients and servers, change your settings to these:

c2s_require_encryption = true
s2s_secure_auth = true

Check your setup

XMPP Observatory

or check your certificates with openssl:

Server: # openssl s_client -connect  -starttls xmpp < /dev/null
Client: # openssl s_client -connect  -starttls xmpp < /dev/null
Top Ten Linux Distributions and https

Top Ten Linux Distributions and https

A/A |  Distro    |          URL               | Verified by       | Begin      | End        | Key
01. | ArchLinux  | | Let's Encrypt     | 02/24/2016 | 05/24/2016 | 2048
02. | Linux Mint |     | COMODO CA Limited | 02/24/2016 | 02/24/2017 | 2048
03. | Debian     |    | Gandi             | 12/11/2015 | 01/21/2017 | 3072
04. | Ubuntu     |      | -                 | -          | -          | -
05. | openSUSE   |  | DigiCert Inc      | 02/17/2015 | 04/23/2018 | 2048
06. | Fedora     |     | DigiCert Inc      | 11/24/2014 | 11/28/2017 | 4096
07. | CentOS     |    | DigiCert Inc      | 07/29/2014 | 08/02/2017 | 2048
08. | Manjaro    | | DigiCert Inc      | 01/20/2016 | 04/06/2017 | 2048
09. | Mageia     |    | Gandi             | 03/01/2016 | 02/07/2018 | 2048
10. | Kali       |      | GeoTrust Inc      | 11/09/2014 | 11/12/2018 | 2048
Tag(s): https