Introducing proxmox-vm-to-ct

github.com/thushan/proxmox-vm-to-ct

With Proxmox VM to CT you can easily convert your existing VMs to a Container by passing in some basic options. Plus it has some extra lean DietPi optimisations for an even more resource efficient DietPi container!

As it’s a self-contained bash script, you can grab it easily from the github repo:

wget https://raw.githubusercontent.com/thushan/proxmox-vm-to-ct/main/proxmox-vm-to-ct.sh
chmod +x ./proxmox-vm-to-ct.sh

We just finished migrating just over 200 VMs to containers and templating a few for future musings.

For instance, suppose you have a VM called the-matrix that you want to convert to a container named matrix-reloaded and your Proxmox storage is called local-zfs, you can simply call the script like so:

./proxmox-vm-to-ct.sh --source the-matrix \
                      --target matrix-reloaded \
                      --storage local-zfs \
                      --default-config

You can even convert VM’s that you’ve installed Docker, Podman or containerd installations, you can use the --default-config-containerd switch:

./proxmox-vm-to-ct.sh --source the-matrix \
                      --target matrix-reloaded \
                      --storage local-zfs \
                      --default-config-containerd

If you want to keep the source output from the script for future containers, use the --source-output switch:

./proxmox-vm-to-ct.sh --source the-matrix \
                      --target matrix-reloaded \
                      --storage local-zfs \
                      --default-config-containerd \
                      --source-output ~/my-first-vm.tar.gz

Then you can reuse that same template to create more containers:

./proxmox-vm-to-ct.sh --source ~/my-first-vm.tar.gz \
                      --target matrix-revolutions \
                      --storage local-zfs \
                      --default-config-containerd

The --source switch supports two different types of inputs:

• SSH: IP or Hostname (Eg. 192.168.0.101 or thematrix.fritz.box)
• Archive: GZip root file system (Eg. *.tar.gz)

Which renders out something similar to this - on our test rig named gandalf:

Securely set passwords

By default, the script will auto-generate a password for you and set it on the container, but you can opt to have it prompt you for a password with the --prompt-password switch.

It will whip open a whiptail window asking you for a password!

Default Configurations

The default configuration for the script is quite basic, but you can opt to create your own machine/cluster specific configurations inside a (sort of an) env file.

Following the example default.config, create a file with only the settings you want to change from the default:

# loggins-cpu.config
CT_CPU=8
CT_RAM=10240
CT_HDD=500

Then load the configuration overiding the default options:

./proxmox-vm-to-ct.sh --source ~/my-first-vm.tar.gz \
                      --target kenny-loggins \
                      --storage local-zfs \
                      --default-config \
                      --target-config loggins-cpu.config

DietPi optimisations

If your VM is based on DietPi (6.x to 9.x), you can have the script optimise it for Containers by default which is documented here.

• Sets the .dietpi_hw_model_identifier from 21 (x86_64) to 75 (container) as per documentation
• Sets up first-login install sequence (even if you’ve done it already) so each container gets updates and updating of passwords instead of any randomly generated ones from the script by modifying /boot/dietpi/.installstage.
• Stops DietPi-CloudShell which is CloudHell when you reboot as a container in Proxmox otherwise.
• Adds the purging of grub-pc tiny-initramfs linux-image-amd64 packages which aren’t required as a container - see Michalng’s comment.

They can be disabled with --ignore-dietpi and won’t be done on non-dietpi VMs (like Debian etc).

Acknowledgements

This script uses the handiwork by @my5t3ry/machine-to-proxmox-lxc-ct-converter and in particular the change by blauskaerm that tar’s up the filesystem.

References

• Examples of usage
• Usage options
• Default Configuration
• Default Containerd Configuration
• DietPi Changes