This is an experimental prometheus exporter to get some stats for Ceph RBD that don't seem to be available elsewhere. Specifically, looking to get the output of the following command into prometheus:
rbd mirror pool status <pool>
See https://docs.ceph.com/en/reef/rbd/rbd-mirroring/#mirror-status for more info on what this does.
The capabilities of this exporter might grow over time.