Ceph » RADOS

Running ceph-mon with the --extract-monmap flag (which must be done with root privileges apparently) seems to cause some files in the /var/lib/ceph/mon/ceph-{mon_id} to be set to root:root user and group.

This causes restarting the service to fail until someone recursively chown's the parent directory again to ceph:ceph. For a seasoned user to linux this is a minor annoyance w/ easy fix, but might confuse a newbie for a longer period of time.

Steps to reproduce on v15.2.5 (Ubuntu 18.04):

- sudo systemctl stop ceph-mon@{mon_id}.service
- ceph-mon i {mon_id} --extract-monmap monmap.bin
sudo systemctl start ceph-mon@{mon_id}.service <-- this will fail, journalctl will show permissions error upon inspection.

Possible resolution:

Have ceph-mon record the permission of the user before running and set them back to that user after completion. Or perhaps they are new files being created, but the help suggests the flag is only reading info not writing anything.