The purpose of this blog post is to act as a visual guide/tutorial on how to setup an iOS device (iPad or iPhone) using the native apps against a custom Linux Mail, Calendar & Contact server.

Disclaimer: I wrote this blog post after 36hours with an apple device. I have never had any previous encagement with an apple product. Huge culture change & learning curve. Be aware, that the below notes may not apply to your setup.

Original creation date: Friday 12 Oct 2018
Last Update: Sunday 18 Nov 2018

Linux Mail Server

Notes are based on the below setup:

• CentOS 6.10
• Dovecot IMAP server with STARTTLS (TCP Port: 143) with Encrypted Password Authentication.
• Postfix SMTP with STARTTLS (TCP Port: 587) with Encrypted Password Authentication.
• Baïkal as Calendar & Contact server.

Thunderbird

Thunderbird settings for imap / smtp over STARTTLS and encrypted authentication

Baikal

Dashboard

CardDAV

contact URI for user Username

https://baikal.baikal.example.org/html/card.php/addressbooks/Username/default

CalDAV

calendar URI for user Username

https://baikal.example.org/html/cal.php/calendars/Username/default

iOS

There is a lot of online documentation but none in one place. Random Stack Overflow articles & posts in the internet. It took me almost an entire day (and night) to figure things out. In the end, I enabled debug mode on my dovecot/postifx & apache web server. After that, throught trail and error, I managed to setup both iPhone & iPad using only native apps.

Mail

Open Password & Accounts & click on New Account

Choose Other

Now the tricky part, you have to click Next and fill the imap & smtp settings.

Now we have to go back and change the settings, to enable STARTTLS and encrypted password authentication.

STARTTLS with Encrypted Passwords for Authentication

In the home-page of the iPad/iPhone we will see the Mail-Notifications have already fetch some headers.

and finally, open the native mail app:

Contact Server

Now ready for setting up the contact account

https://baikal.baikal.example.org/html/card.php/addressbooks/Username/default

Opening Contact App:

Calendar Server

https://baikal.example.org/html/cal.php/calendars/Username/default

Cloud-init is the defacto multi-distribution package that handles early initialization of a cloud instance

This article is a mini-HowTo use cloud-init with centos7 in your own libvirt qemu/kvm lab, instead of using a public cloud provider.

How Cloud-init works

Josh Powers @ DebConf17

How really works?

Cloud-init has Boot Stages

• Generator
• Local
• Network
• Config
• Final

and supports modules to extend configuration and support.

Here is a brief list of modules (sorted by name):

• bootcmd
• final-message
• growpart
• keys-to-console
• locale
• migrator
• mounts
• package-update-upgrade-install
• phone-home
• power-state-change
• puppet
• resizefs
• rsyslog
• runcmd
• scripts-per-boot
• scripts-per-instance
• scripts-per-once
• scripts-user
• set_hostname
• set-passwords
• ssh
• ssh-authkey-fingerprints
• timezone
• update_etc_hosts
• update_hostname
• users-groups
• write-files
• yum-add-repo

Gist

Cloud-init example using a Generic Cloud CentOS-7 on a libvirtd qmu/kvm lab · GitHub

Generic Cloud CentOS 7

You can find a plethora of centos7 cloud images here:

• cloud centos images

Download the latest version

$ curl -LO http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.qcow2.xz

Uncompress file

$ xz -v --keep -d CentOS-7-x86_64-GenericCloud.qcow2.xz

Check cloud image

$ qemu-img info CentOS-7-x86_64-GenericCloud.qcow2

image: CentOS-7-x86_64-GenericCloud.qcow2
file format: qcow2
virtual size: 8.0G (8589934592 bytes)
disk size: 863M
cluster_size: 65536
Format specific information:
    compat: 0.10
    refcount bits: 16

The default image is 8G.
If you need to resize it, check below in this article.

Create metadata file

meta-data are data that comes from the cloud provider itself. In this example, I will use static network configuration.

cat > meta-data <<EOF
instance-id: testingcentos7
local-hostname: testingcentos7

network-interfaces: |
  iface eth0 inet static
  address 192.168.122.228
  network 192.168.122.0
  netmask 255.255.255.0
  broadcast 192.168.122.255
  gateway 192.168.122.1

# vim:syntax=yaml
EOF

Crete cloud-init (userdata) file

user-data are data that comes from you aka the user.

cat > user-data <<EOF
#cloud-config

# Set default user and their public ssh key
# eg. https://github.com/ebal.keys
users:
  - name: ebal
    ssh-authorized-keys:
      - `curl -s -L https://github.com/ebal.keys`
    sudo: ALL=(ALL) NOPASSWD:ALL

# Enable cloud-init modules
cloud_config_modules:
  - resolv_conf
  - runcmd
  - timezone
  - package-update-upgrade-install

# Set TimeZone
timezone: Europe/Athens

# Set DNS
manage_resolv_conf: true
resolv_conf:
  nameservers: ['9.9.9.9']

# Install packages
packages:
  - mlocate
  - vim
  - epel-release

# Update/Upgrade & Reboot if necessary
package_update: true
package_upgrade: true
package_reboot_if_required: true

# Remove cloud-init
runcmd:
  - yum -y remove cloud-init
  - updatedb

# Configure where output will go
output:
  all: ">> /var/log/cloud-init.log"

# vim:syntax=yaml
EOF

Create the cloud-init ISO

When using libvirt with qemu/kvm the most common way to pass the meta-data/user-data to cloud-init, is through an iso (cdrom).

$ genisoimage -output cloud-init.iso -volid cidata -joliet -rock user-data meta-data

or

$ mkisofs -o cloud-init.iso -V cidata -J -r user-data meta-data

Provision new virtual machine

Finally run this as root:

# virt-install
    --name centos7_test
    --memory 2048
    --vcpus 1
    --metadata description="My centos7 cloud-init test"
    --import
    --disk CentOS-7-x86_64-GenericCloud.qcow2,format=qcow2,bus=virtio
    --disk cloud-init.iso,device=cdrom
    --network bridge=virbr0,model=virtio
    --os-type=linux
    --os-variant=centos7.0
    --noautoconsole

The List of Os Variants

There is an interesting command to find out all the os variants that are being supported by libvirt in your lab:

eg. CentOS

$ osinfo-query os | grep CentOS

centos6.0  |  CentOS  6.0  |  6.0  |  http://centos.org/centos/6.0
centos6.1  |  CentOS  6.1  |  6.1  |  http://centos.org/centos/6.1
centos6.2  |  CentOS  6.2  |  6.2  |  http://centos.org/centos/6.2
centos6.3  |  CentOS  6.3  |  6.3  |  http://centos.org/centos/6.3
centos6.4  |  CentOS  6.4  |  6.4  |  http://centos.org/centos/6.4
centos6.5  |  CentOS  6.5  |  6.5  |  http://centos.org/centos/6.5
centos6.6  |  CentOS  6.6  |  6.6  |  http://centos.org/centos/6.6
centos6.7  |  CentOS  6.7  |  6.7  |  http://centos.org/centos/6.7
centos6.8  |  CentOS  6.8  |  6.8  |  http://centos.org/centos/6.8
centos6.9  |  CentOS  6.9  |  6.9  |  http://centos.org/centos/6.9
centos7.0  |  CentOS  7.0  |  7.0  |  http://centos.org/centos/7.0

DHCP

If you are not using a static network configuration scheme, then to identify the IP of your cloud instance, type:

$ virsh net-dhcp-leases default

 Expiry Time           MAC address         Protocol   IP address           Hostname   Client ID or DUID
---------------------------------------------------------------------------------------------------------
 2018-11-17 15:40:31   52:54:00:57:79:3e   ipv4       192.168.122.144/24   -          -                  

Resize

The easiest way to grow/resize your virtual machine is via qemu-img command:

$ qemu-img resize CentOS-7-x86_64-GenericCloud.qcow2 20G

Image resized.

$ qemu-img info CentOS-7-x86_64-GenericCloud.qcow2

image: CentOS-7-x86_64-GenericCloud.qcow2
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 870M
cluster_size: 65536
Format specific information:
    compat: 0.10
    refcount bits: 16

You can add the below lines into your user-data file

growpart:
  mode: auto
  devices: ['/']
  ignore_growroot_disabled: false

The result:

[root@testingcentos7 ebal]# df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        20G  870M   20G   5% /

Default cloud-init.cfg

For reference, this is the default centos7 cloud-init configuration file.

# /etc/cloud/cloud.cfg 

users:
 - default

disable_root: 1
ssh_pwauth:   0

mount_default_fields: [~, ~, 'auto', 'defaults,nofail', '0', '2']
resize_rootfs_tmp: /dev
ssh_deletekeys:   0
ssh_genkeytypes:  ~
syslog_fix_perms: ~

cloud_init_modules:
 - migrator
 - bootcmd
 - write-files
 - growpart
 - resizefs
 - set_hostname
 - update_hostname
 - update_etc_hosts
 - rsyslog
 - users-groups
 - ssh

cloud_config_modules:
 - mounts
 - locale
 - set-passwords
 - rh_subscription
 - yum-add-repo
 - package-update-upgrade-install
 - timezone
 - puppet
 - chef
 - salt-minion
 - mcollective
 - disable-ec2-metadata
 - runcmd

cloud_final_modules:
 - rightscale_userdata
 - scripts-per-once
 - scripts-per-boot
 - scripts-per-instance
 - scripts-user
 - ssh-authkey-fingerprints
 - keys-to-console
 - phone-home
 - final-message
 - power-state-change

system_info:
  default_user:
    name: centos
    lock_passwd: true
    gecos: Cloud User
    groups: [wheel, adm, systemd-journal]
    sudo: ["ALL=(ALL) NOPASSWD:ALL"]
    shell: /bin/bash
  distro: rhel
  paths:
    cloud_dir: /var/lib/cloud
    templates_dir: /etc/cloud/templates
  ssh_svcname: sshd

# vim:syntax=yaml