I wrote something for myself, and figured it might be useful for others: a small service that automatically discovers LXCs and VMs in a Proxmox cluster and acts as a DNS server pointing to the IP(s) for them. It's called, somewhat unimaginatively... proxmox-service-discovery:
https://github.com/andrew-d/proxmox-service-discovery
As a short example: if you have a Proxmox cluster running lxc1, lxc2, and vm3, and you run proxmox-service-discovery with the "--dns-zone=example.com" option, then it will run a DNS server that answers queries for lxc1.example.com with all the IP addresses for lxc1, and so on for lxc2 and vm3.
It's pretty basic but well-tested, and seems to work well for my use-case. Feedback appreciated, along with bug reports, PRs, and so on!
