Ceph » mgr

a) ceph-mgrs keys and bootstrap process and verify properly bootstraped

We have manual setup instructions, they just happen not to use the bootstrap key. I don't think that part really belongs in the user documentation, as it's only for people writing things like ceph-deploy and ceph-ansible, and even then it's sort of optional (a tool writer can always use their admin key to create mgr keys).

While it would be nice to have some higher level design documentation that explains the process by which things like ceph-deploy set up keys for services, this is not specific to the mgr.

b) co-location of ceph-mgr with mon is recommended ? and there can be just one mgr but more mons for quorum ?

See http://docs.ceph.com/docs/master/mgr/administrator/#high-availability

c) is it required to manually start/stop after mon is restarts ? how to debug "No Mgr" ?

In general, I think it's reasonably obvious that "no mgr" type warnings should prompt someone to go and check their mgr daemons are running: I'm honestly not sure what I would write in the documentation to make that any clearer.

If there are specific common issues preventing mgr daemons from starting, then I'm happy to have a FAQ/troubleshooting page for those though.

d) is only mandatory after jewel+

Second paragraph on http://docs.ceph.com/docs/master/mgr/