check_ceph_num_osds check breaks on Octopus and newer

[Paul Goins]

In newer versions of ceph, the JSON output of ceph status no longer uses a doubly-nested osdmap. This breaks the check_ceph_num_osds NRPE check.

Specifically, this appears to have been introduced in version 15.1.0 of Ceph Octopus.

The check needs to be updated to check these values in either their old or new location. As is, the check fails, returning an UNKNOWN status to Nagios, with the output "check_ceph_status raised unknown exception '<class 'KeyError'>'".

Upstream reference: https://github.com/ceph/ceph/commit/f222c7bb1790f4ab3e8e0afd0c7915ed84f0c6c8
Related chatter which lead me to the above: https://github.com/ceph/ceph-ansible/issues/5400#issuecomment-638832176

[Pedro Castillo (peterctl)]

I submitted a PR for this a couple of days ago.
https://review.opendev.org/c/openstack/charm-ceph-mon/+/841341

[OpenStack Infra (hudson-openstack)]

Change abandoned by "James Page <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/charm-ceph-mon/+/841341
Reason: This review is > 12 weeks without comment, and failed testing the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.