For me, I have three proxmox nodes that are configured to restart VMs and LXC containers if a host goes offline. There’s a Palo Alto pa-440 for my fw/router and a brocade switch (they were something work gave me for practicing for a network exam).
The nodes, Palo, brocade, and AT&T modem are all on two UPS 1500va systems along with my wifi ap. Run time in case of power loss is around an hour.
I’m this close to getting a comprehensive shutdown script working from a raspberry pi that is triggered if there’s power loss (most UPS systems have some capability to trigger scripts on a host that’s connected to the UPS’s console port).
If I can get that script working, the battery backup will run a PI for several days.
Back on the redundancy side, I host two PowerDNS systems in the proxmox cluster along with a 3 node/LXC container Vault.
Yup, shared storage is a requirement. I’m using a combination of Ceph and NFS at the moment, but I wouldn’t recommend Ceph unless you’ve got a 10gb connection between nodes.
Here’s a guide to set up high availability with Proxmox: https://kiwicloud.ninja/2024/02/improved-high-availability-ha-for-vms-on-proxmox-ve-pve/