Create an LXC container in Proxmox outside of pre-packaged templates

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March 25, 2025

• Let's say you want to run Debian 13 (Trixie), but there is no standard template for it in Proxmox. What do you do?

LinuxContainers.org for the rescue!

• Such cases may happen but do not worry, there is a way around it! Simply go to LinuxContainers.org and find your desired one. You will find that the actual image name is called 'rootfs.tar.xz'.

• Head to your Proxmox node and connect to it via shell or via SSH.
• Go to the following folder and download + rename the CT image:

cd /var/lib/vz/template/cache/
# Replace the URL of the one you are after
wget https://images.linuxcontainers.org/images/debian/trixie/amd64/cloud/20250628_05:24/rootfs.tar.xz
# Rename it to something that makes sense to you:
mv rootfs.tar.xz debian-13-trixie-lxc-2025-06-28.tar.xz

• Now you could head to Proxmox's GUI and create the container from there. However, if you are on Proxmox 8 (which is powered by Debian 12) and try creating a CT with Debian 13, you will inevitably hit an issue with the new networking service that is used in Trixie:

• The way around it is to create the container from the Proxmox shell and skip the networking part initially.

pct create <CT_ID> \
/var/lib/vz/template/cache/debian-13-trixie-lxc-2025-06-28.tar.xz \
--storage <YOUR_STORAGE> \
--rootfs <YOUR_STORAGE>:10 \
--hostname <HOSTNAME> \
--memory 1024 \
--cores 1 \
--password <YOUR_PASSWORD>

• Replace the values as follows:
  • : Choose an available one.
  • : local storage name such as 'local-lvm'.
  • : Name of the CT, such as deb13
  • : Root password to log in with. Do not use special characters.
• And voila, straight after passing the command, I can see the result in Proxmox's GUI tab:

• When viewing from Proxmox's web GUI, you will notice that there is no network tab in there:

• Now we can continue using the Proxmox shell to start the container (or you can do so from the GUI), log into it and create a folder in which the network adapter will be created later.

# Start the container
pct start <CT_ID>

# Enter the container's command line
pct enter <CT_ID>

# Inside the container, create the directory
mkdir /etc/network

# Exit the container's shell
exit

# Shut the container down so we can add the network device
pct shutdown <CT_ID>

# Add a network interface to the container (assuming you use vmbr0 for LAN and are okay with DHCP)
pct set <CT_ID> --net0 name=eth0,bridge=vmbr0,ip=dhcp

# Start the container again
pct start <CT_ID>

# Switch the network interface on + add DHCP
ip link set eth0 up
dhclient eth0

# Verify connectivity
ip addr | grep eth0

# To make it pernament, run the following:
apt update
apt install ifupdown2
reboot

• What we did there by creating the folder and assigning the port was to make the generic Debian 13 image compatible with the way Proxmox manages a container's network configuration, until Proxmox itself gets updated to work with it smoothly.
• This means that this article may not age well, but the idea behind it remains.

Takeaways

In summary, you can:

• Download the newest versions of LXC images from trusted sources like LinuxContainers.org
• Use the Proxmox shell to circumvent what the GUI cannot do and even create scripted solutions to start/configure/stop containers.
• Create containers with certain settings missing (like for networking) in case the current version of Proxmox struggles to work with it.

And that is all there is to it!