No way to enable RBD per-image IO statistics optionally using the charm

Just for the record, this is out of the box (empty)

And this is after executing the following by hand.

juju exec --unit ceph-mon/leader 'ceph config set mgr mgr/prometheus/rbd_stats_pools "*"'

Also we would be able to show an informative message in the dashboard itself so nobody has to wonder why it has no data.

POC patch:
https://github.com/nobuto-m/ceph/commit/8a6974eb86abb667bab9afe1d9950f940363d81a

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/charm-ceph-mon/+/900153

Reviewed: https://review.opendev.org/c/openstack/charm-ceph-mon/+/900153
Committed: https://opendev.org/openstack/charm-ceph-mon/commit/ffe81367e10eaf8c6fecc96f3c442eb471354bbc
Submitter: "Zuul (22348)"
Branch: master

commit ffe81367e10eaf8c6fecc96f3c442eb471354bbc
Author: Samuel Walladge <email address hidden>
Date: Mon Nov 6 17:11:19 2023 +1030

    Add config option for rbd_stats_pools

    This allows configuration RBD IO statistics collection for RBD pools.

    Co-authored-by: Yoshi Kadokawa <email address hidden>

    Closes-Bug: #2042405

    Related-Bug: #1989648
    Change-Id: I2252163533a312f0f53165f946711ab20bb0e3c9

Fix proposed to branch: stable/quincy.2
Review: https://review.opendev.org/c/openstack/charm-ceph-mon/+/900899

Reviewed: https://review.opendev.org/c/openstack/charm-ceph-mon/+/900899
Committed: https://opendev.org/openstack/charm-ceph-mon/commit/398c34ae05af9905c267f4847a2c36133913d7ea
Submitter: "Zuul (22348)"
Branch: stable/quincy.2

commit 398c34ae05af9905c267f4847a2c36133913d7ea
Author: Samuel Walladge <email address hidden>
Date: Mon Nov 6 17:11:19 2023 +1030

    Add config option for rbd_stats_pools

    This allows configuration RBD IO statistics collection for RBD pools.

    Co-authored-by: Yoshi Kadokawa <email address hidden>

    Closes-Bug: #2042405

    Related-Bug: #1989648
    Change-Id: I2252163533a312f0f53165f946711ab20bb0e3c9
    (cherry picked from commit ffe81367e10eaf8c6fecc96f3c442eb471354bbc)

It seems juju would fail if the value is empty.

2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: 2024-01-06 05:47:06 WARNING unit.ceph-mon/0.config-changed logger.go:60 Error EINVAL: unrecognized config option 'mgr/prometheus/rbd_stats_pools'
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: 2024-01-06 05:47:06 ERROR unit.ceph-mon/0.juju-log server.go:316 Uncaught exception while in charm code:
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: Traceback (most recent call last):
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "./src/charm.py", line 310, in <module>
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: main(CephMonCharm)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/ops/main.py", line 436, in main
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: _emit_charm_event(charm, dispatcher.event_name)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/ops/main.py", line 144, in _emit_charm_event
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: event_to_emit.emit(*args, **kwargs)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/ops/framework.py", line 351, in emit
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: framework._emit(event)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/ops/framework.py", line 853, in _emit
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: self._reemit(event_path)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/ops/framework.py", line 942, in _reemit
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: custom_handler(event)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/ops_openstack/core.py", line 260, in _on_config
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: self.on_config(event)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "./src/charm.py", line 87, in on_config
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: if hooks.config_changed():
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/charmhelpers/contrib/hardening/harden.py", line 90, in _harden_inner2
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: return f(*args, **kwargs)
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/src/ceph_hooks.py", line 381, in config_changed
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: mgr_config_set_rbd_stats_pools()
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/src/utils.py", line 427, in mgr_config_set_rbd_stats_pools
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: ceph_utils.mgr_config_set(
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: File "/var/lib/juju/agents/unit-ceph-mon-0/charm/venv/charms_ceph/utils.py", line 3569, in ceph_config_set
2024-01-06 05:47:08 [ERROR] unit-ceph-mon-0.log: subprocess.check_call(['ceph', 'config', 'set', who, name, value])
2024-...

When the value is empty, it seems to execute:
ceph config set mgr mgr/prometheus/rbd_stats_pools

But it should execute:
ceph config set mgr mgr/prometheus/rbd_stats_pools ''

May need to update charms_ceph/utils.py to handle empty values properly

After some more tests, it turns out that this command will fail no matter if I give it a value or not.
It seems the command is executed too early and at that time ceph mon is not initiated yet.

2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:05:59 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Ceph is not bootstrapped, skipping upgrade checks.
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:05:59 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Monitor hosts are ['10.5.2.27']
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:00 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Settings for the cluster are: {'fsid': '0be52cf2-ac62-11ee-8f8a-9109e1518e46', 'monitor-secret': 'AQDY+5hlxaxyChAA1kj4CSKU3tq2z1uDNTUgGg=='}
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:00 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Making dir /var/lib/charm/secondary-ceph-mon ceph:ceph 555
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:00 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Making dir /var/run/ceph ceph:ceph 755
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:00 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Making dir /var/lib/ceph/mon/ceph-juju-9d6cae-zaza-34cc90b87300-5 ceph:ceph 755
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:00 WARNING unit.secondary-ceph-mon/0.config-changed logger.go:60 Created symlink /<email address hidden> → /lib/systemd/system/ceph-mon@.service.
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:01 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Waiting for quorum to be reached
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:04 WARNING unit.secondary-ceph-mon/0.config-changed logger.go:60 2024-01-06T07:06:04.580+0000 7f9d064f9700 -1 auth: unable to find a keyring on /var/lib/ceph/mon/ceph-/keyring: (2) No such file or directory
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:04 WARNING unit.secondary-ceph-mon/0.config-changed logger.go:60 2024-01-06T07:06:04.580+0000 7f9d064f9700 -1 AuthRegistry(0x7f9d00060240) no keyring found at /var/lib/ceph/mon/ceph-/keyring, disabling cephx
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:04 INFO unit.secondary-ceph-mon/0.juju-log server.go:316 Making dir /var/lib/ceph/mgr/ceph-juju-9d6cae-zaza-34cc90b87300-5 ceph:ceph 555
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:05 WARNING unit.secondary-ceph-mon/0.config-changed logger.go:60 Created symlink /<email address hidden> → /lib/systemd/system/ceph-mgr@.service.
2024-01-06 07:06:08 [ERROR] unit-secondary-ceph-mon-0.log: 2024-01-06 07:06:07 WARNING unit.secondary-ceph-mon/0.config-changed logger.go:60 Error EINVAL: unrecognized config option 'mgr/prometheus/rbd_stats_pools'

Maybe it needs to wait until mon is bootstrapped then run the com...

The command is guarded by ceph_utils.is_bootstrapped() already so it sounds like a race condition whether the mgr and the module is enabled by that point.

Do you have a minimal reproducer e.g. bundle to trigger this reliably?

We've hit this issue during CI runs of the radosgw charm, AFAIK that's a reliable reproducer.

This latest bug in particular is being handled here: https://review.opendev.org/c/openstack/charm-ceph-mon/+/904594

The fix in ceph-mon charm r199 works! Thanks for looking into this.

Related fix proposed to branch: stable/quincy.2
Review: https://review.opendev.org/c/openstack/charm-ceph-mon/+/914836

Reviewed: https://review.opendev.org/c/openstack/charm-ceph-mon/+/914836
Committed: https://opendev.org/openstack/charm-ceph-mon/commit/01bd228242a1fe437e9f0f544aa4b4e093c56e2d
Submitter: "Zuul (22348)"
Branch: stable/quincy.2

commit 01bd228242a1fe437e9f0f544aa4b4e093c56e2d
Author: Luciano Lo Giudice <email address hidden>
Date: Wed Jan 3 18:10:30 2024 -0300

    Retry setting rbd_stats_pools prometheus config

    Setting the 'mgr/prometheus/rbd_stats_pools' option can fail
    if we arrive too early, even if the cluster is bootstrapped. This is
    particularly seen in ceph-radosgw test runs. This patchset thus
    adds a retry decorator to work around this issue.

    Related-Bug: #2042405
    Related-Bug: #2058636

    Change-Id: Id9b7b903e67154e7d2bb6fecbeef7fac126804a8
    (cherry picked from commit d76939ef70bd5016a6e515558de1b9eabe9d0d55)