Ref: export storage pool metrics for prometheus · Issue #2097 · lxc/incus · GitHub
The good news is, incusOS should already merge in node_exporter metrics - look for metrics like node_zfs_zpool_state. (I don’t have an incusOS host to test this)
The bad news is, node_exporter currently doesn’t give the overall zpool utilization figures. Feat: Report ZFS pool and volume size/alloc/free · Issue #3232 · prometheus/node_exporter · GitHub - I have tested this with the latest node_exporter 1.11.1
I don’t know how the incusOS UI gets its data, but I guess it’s via the incus API.