If you wonder how to automate Ubuntu virtual machine creation and then deploy it to Proxmox in multple copies, then you are looking for Packer and Terraform. Side note: going for virtual machines in Proxmox is the proper way. I tried for several days to have LXC containers working, however finally I will say that it is not the best option with lot of things going bad like cgroups, AppArmor, nesting, FUSE, ingress networking etc. There is literally too much to handle with LXC and with VM there is no such problem, so discussion end here in favour of Proxmox