Hi Zorillas and interested parties,
(Copying a couple of folks explicitly as they may not be part of openstack-discuss)
Manila's CephFS driver has a configuration option "cephfs_enable_snapshots" that administrators can toggle in manila.conf to allow project users to take snapshots of their shares. [1][2] This option has defaulted to False, since the time the CephFS driver was introduced (Mitaka release of OpenStack Manila)
IIUC, CephFS snapshots have been "stable" since the Mimic release of CephFS, which debuted in June 2018. [3] Since then, ceph deployers/administrators don't have to toggle anything on the backend to enable snapshots.
So, can we consider changing the default value of the config opt in manila to "True" in the Train release? This will allow the driver to report the capability "snapshot_support" as enabled, and makes life easier for OpenStack deployers/administrators. I would also love to deprecate this option and remove it in a future release, since it isn't really necessary, read on:
Users cannot arbitrarily take snapshots in manila, there are a couple of things that can be used to prevent them: Quotas and Share Types. Unless users create their shares using a share type that explicitly requests "snapshot_support", users can't snapshot their shares. So, we're covered by the service's API in case someone is afraid this has an impact on someone in the wild using newer versions of Manila with older versions of Ceph, where snapshots were unstable.
Thoughts?
[1] https://opendev.org/openstack/manila/src/commit/721bb70a81b80bf065705e8790bd... [2] https://docs.openstack.org/manila/queens/admin/cephfs_driver.html#enabling-s... [3] http://docs.ceph.com/docs/mimic/dev/cephfs-snapshots/