Build your own Proxmox LXC Template
Start off in the Proxmox web GUI by creating a normal LXC container using one of the existing templates. I chose Debian 12 here.
Start it up and install/customise anything you want. I installed docker on mine since i use this a lot and it saves a step.
Once finished, shutdown the LXC container.
Go to your Proxmox node's shell.
Enter the following commands where 250
is your container's ID in Proxmox...
pct set 250 --delete net0
vzdump 250 --mode stop --compress gzip --dumpdir /tmp/
cd /tmp
Rename the image here...
mv vzdump*.tar.gz my-custom-debian-lxc.tar.gz
I have an NFS share that I store my ISOs and templates on so I'm going to move it there...
mv my-custom-debian-lxc.tar.gz /mnt/pve/ISOs/template/cache/
If you go to the ISOs volume in the Proxmox GUI and choose CT Templates you should now see your new image.
You can then create containers using this image.