Ceph » mgr

Allow the mgr/prometheus module to collect RBD per-pool stats.

Such stats are now available via `rbd pool stats` command.

❯ rbd pool stats -p my_awesome_pool
Total Images: 50456 (58 in trash)
Total Snapshots: 55763 (169 in trash)
Provisioned Size: 957 TiB (876 GiB in trash)

The main goal is to facilitate trash usage monitoring for highly dynamic setups where thousands of images and snapshots are created and trashed daily.

Such a feature could be optionally enabled in the likeness of RBD per-image stats: https://docs.ceph.com/en/latest/mgr/prometheus/#rbd-io-statistics

The mgr/prometheus module is already using the python rbd library: https://github.com/ceph/ceph/blob/cb2b48d76f56fc07bc6a177ed79951f825d2165e/src/pybind/mgr/prometheus/module.py#L1533C9

So it should be possible to utilize the `pool_stats_get` function https://docs.ceph.com/en/reef/rbd/api/librbdpy/#rbd.RBD.pool_stats_get for obtaining the required data.