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Debian CloudInit Template VM Configuration and Deployment

Part 1 - VM Template Creation and Preparation

Download the latest copy of Debian's NetInstall ISO image from here.

For this article, we'll be using https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-11.2.0-amd64-netinst.iso

Upload/Save the file to your ISO Datastore.

Deploy a New VM from Xen Orchestra and boot from the ISO we just downloaded.
Give it between 2-4CPU, and 2-4GB of RAM.

When the VM boots, select "Install" instead of "Graphical Install" - this will create a cli only server instance with no Desktop environment.

Navigate through the prompts and Select your language, location and keyboard layout (keymap).

Give your device a hostname. In this example, we used Hostname "debianTemplate"

Skip adding a Domain name for now.

Skip creating a root password - we'll give the tempuser account below root access

Enter a name for the new user and enter the user's password

Enter your TimeZone

When you get up to the Disk Partition Stage, select "Manual"
Navigate down and select your virtual disk and press enter
Select "Yes"
Select your newly created primary partition and press enter
Select "Create a new partition"
Enter your partition size and press enter

This will be a Primary partition:

Looks good to me!
Write the partition layout to disk.

Do not add a swap space if prompted. I.E Do not return to the partition menu.

Select "Yes" when prompted with the summary to write the changes to the disk.
The Base System will install - this might take several minutes depending on your device.

When that completes, select "no" when prompted to scan additional media 

Select your country and Debian Mirror. You can press enter to skip HTTP proxy and select No to skip the package usage survey

Press the SpaceBar to unselect the "Debian Desktop Environment" and "GNOME" packages and enable the SSH server package and press enter to continue.

When prompted, select "Yes" to install Grub on the Primary Device
Find your virtual disk and hit enter 

After this, the VM will want to reboot

Press enter to reboot and eject the installation media.

This concludes Part 1.

Part 2 - Initial VM template Customisation

Once the VM has rebooted, Insert the Guest Tools ISO via Xen Orchestra.

Sign in through the Xen Orchestra web UI console (or if you know the ip address of the VM, ssh to it) and install the Guest Tools with this single liner:

sudo mount /dev/cdrom /mnt && sudo bash /mnt/Linux/install.sh -n && sudo reboot now

When the VM reboots, it should change from having "No Xen tools detected" and no IP address listed to showing the OS version, IP address and Management agent version

before
after

Now we know the IP address, we can ssh to it.

enter the tempuser password from part1

Run the following (each line is a new command):

sudo apt install cloud-utils
sudo apt install cloud-init
sudo apt install cloud-initramfs-growroot
cd /etc/cloud
sudo nano cloud.cfg


Delete everything in the default cloud.cfg file by pressing ctrl+k to remove lines from the file until it's empty. Copy the following into your clipboard and right click in nano to paste the contents:

cloud.cfg
cloud.cfg.txt
3 KB
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Press CTRL+O to save, press enter to keep the same filename and then CTRL+X to quit.

Remove root access by running

sudo passwd -l root

Final Step is to enable Cloudinit to take affect on next boot.
Run:

sudo systemctl enable cloud-init

Once this has completed, power off the VM and convert it to a template.

Part 3 - Booting the cloudinit VM