I’ve listened two audiobooks this month, both on DevOps methodology or more accurate on continuous improving of streamflow.

also started audible - amazon for listening audiobooks. The android app is not great but decent enough, although most of the books are DRM.

The first one is The Goal - A Process of Ongoing Improvement by: Eliyahu M. Goldratt, Jeff Cox

I can not stress this enough: You Have To Read this book. This novel is been categorized under business and it is been written back in 1984. You will find innovating even for today’s business logic. This book is the bases of “The Phoenix Project” and you have to read it before the The Phoenix Project. You will understand in details how lean and agile methodologies drive us to DevOps as a result of Ongoing Improvement.

https://www.audible.com/pd/Business/The-Goal-Audiobook/B00IFG88SM

The second book is The DevOps Handbook or How to Create World-Class Agility, Reliability, and Security in Technology Organizations by By: Gene Kim, Patrick Debois, John Willis, Jez Humble Narrated by: Ron Butler

I have this book in both hardcopy and audiobook. It is indeed a handbook. If you are just now starting on devops you need to read it. Has stories of companies that have applied the devops practices and It is really well structured. My suggestion is to keep notes when reading/listening to this book. Keep notes and re-read them.

https://www.audible.com/pd/Business/The-DevOps-Handbook-Audiobook/B0767HHZLZ

systemd

Latest systemd version now contains the systemd-importd daemon .

That means that we can use machinectl to import a tar or a raw image from the internet to use it with the systemd-nspawn command.

so here is an example

machinectl

from my archlinux box:

# cat /etc/arch-release

Arch Linux release

CentOS 7

We can download the tar centos7 docker image from the docker hub registry:

# machinectl pull-tar --verify=no https://github.com/CentOS/sig-cloud-instance-images/raw/79db851f4016c283fb3d30f924031f5a866d51a1/docker/centos-7-docker.tar.xz

...
Created new local image 'centos-7-docker'.
Operation completed successfully.
Exiting.

we can verify that:

# ls -la /var/lib/machines/centos-7-docker

total 28
dr-xr-xr-x 1 root root   158 Jan  7 18:59 .
drwx------ 1 root root   488 Feb  1 21:17 ..
-rw-r--r-- 1 root root 11970 Jan  7 18:59 anaconda-post.log
lrwxrwxrwx 1 root root     7 Jan  7 18:58 bin -> usr/bin
drwxr-xr-x 1 root root     0 Jan  7 18:58 dev
drwxr-xr-x 1 root root  1940 Jan  7 18:59 etc
drwxr-xr-x 1 root root     0 Nov  5  2016 home
lrwxrwxrwx 1 root root     7 Jan  7 18:58 lib -> usr/lib
lrwxrwxrwx 1 root root     9 Jan  7 18:58 lib64 -> usr/lib64
drwxr-xr-x 1 root root     0 Nov  5  2016 media
drwxr-xr-x 1 root root     0 Nov  5  2016 mnt
drwxr-xr-x 1 root root     0 Nov  5  2016 opt
drwxr-xr-x 1 root root     0 Jan  7 18:58 proc
dr-xr-x--- 1 root root   120 Jan  7 18:59 root
drwxr-xr-x 1 root root   104 Jan  7 18:59 run
lrwxrwxrwx 1 root root     8 Jan  7 18:58 sbin -> usr/sbin
drwxr-xr-x 1 root root     0 Nov  5  2016 srv
drwxr-xr-x 1 root root     0 Jan  7 18:58 sys
drwxrwxrwt 1 root root   140 Jan  7 18:59 tmp
drwxr-xr-x 1 root root   106 Jan  7 18:58 usr
drwxr-xr-x 1 root root   160 Jan  7 18:58 var

systemd-nspawn

Now test we can test it:

[root@myhomepc ~]# systemd-nspawn --machine=centos-7-docker

Spawning container centos-7-docker on /var/lib/machines/centos-7-docker.
Press ^] three times within 1s to kill container.

[root@centos-7-docker ~]#
[root@centos-7-docker ~]#
[root@centos-7-docker ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[root@centos-7-docker ~]#
[root@centos-7-docker ~]# exit
logout
Container centos-7-docker exited successfully.

and now returning to our system:

[root@myhomepc ~]#
[root@myhomepc ~]#
[root@myhomepc ~]# cat /etc/arch-release
Arch Linux release

Ubuntu 16.04.4 LTS

ubuntu example:

# machinectl pull-tar --verify=no https://github.com/tianon/docker-brew-ubuntu-core/raw/46511cf49ad5d2628f3e8d88e1f8b18699a3ad8f/xenial/ubuntu-xenial-core-cloudimg-amd64-root.tar.gz

# systemd-nspawn --machine=ubuntu-xenial-core-cloudimg-amd64-root

Spawning container ubuntu-xenial-core-cloudimg-amd64-root on /var/lib/machines/ubuntu-xenial-core-cloudimg-amd64-root.
Press ^] three times within 1s to kill container.
Timezone Europe/Athens does not exist in container, not updating container timezone.
root@ubuntu-xenial-core-cloudimg-amd64-root:~# 

root@ubuntu-xenial-core-cloudimg-amd64-root:~# cat /etc/os-release 

NAME="Ubuntu"
VERSION="16.04.4 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.4 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial

root@ubuntu-xenial-core-cloudimg-amd64-root:~# exit

logout
Container ubuntu-xenial-core-cloudimg-amd64-root exited successfully.

# cat /etc/os-release 

NAME="Arch Linux"
PRETTY_NAME="Arch Linux"
ID=arch
ID_LIKE=archlinux
ANSI_COLOR="0;36"
HOME_URL="https://www.archlinux.org/"
SUPPORT_URL="https://bbs.archlinux.org/"
BUG_REPORT_URL="https://bugs.archlinux.org/"