This was initially reported by jrosser on discuss at https://discuss.elastic.co/t/metricbeat-ceph-stats-collection-breaks-for-ceph-mimic-release/137496

Metricbeat's Ceph module queries the API provided by ceph-rest-api, a command-line tool provided with Ceph versions up to Luminous. This is documented here:

http://docs.ceph.com/docs/luminous/man/8/ceph-rest-api/

This was deprecated under Luminous and has been removed completely from the latest Ceph release, Mimic. (See "Notable Changes" on this page: https://ceph.com/releases/v12-2-5-luminous-released/ )

The replacement is the more comprehensive and more secure Restful plugin for the ceph-mgr service. This is documented here:

http://docs.ceph.com/docs/mimic/mgr/restful/

This uses HTTPS and requires authentication by the client: see

https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/3/html/ceph_management_api/restful-api#enabling-and-securing-the-restful-plug-in

It would be great if MetricBeat understood the new Ceph API for collecting stats.