Just putting this out there if anyone else ever tries it: Don’t do it.
Just create a VM and install it with Docker there.
I spent ~3 hours trying to get it work and even in an unprivileged container with nesting and keyctl enabled, I got can't get final child's PID from pipe: EOF: unknown "proxmox" errors when the redis broker and db were initializing.
I also tried running it in a privileged container but that gave me AppArmor issues.
I also tried running it in Ubuntu and Fedora containers but the same errors appeared.
Interesting. I’ve run with docker inside Xen (XCP-ng), same on VMWare ESXi, now on metal inside apptainer, but I’ve never tried the facilities for running a container directly within any hypervisor. I’ve been tempted to try though.
Well that explains things a bit, I had a helluva time trying to install this way and could never it to work, installed on bare metal and no issue, that was a year or so ago tho. I have since moved over to xcp-ng so will just do a vm since xen doesn’t do lxc.