Ceph » RADOS

"ceph osd ok-to-stop" accepts only integers, "any", and "all". However, the "mon" and "mds" versions accept any string, regardless of whether it is a valid daemon name. They then say that everything will be fine:

root@dc-3558-422:~# ceph mon stat
e1: 3 mons at {dc-3558-422=[v2:10.1.152.122:3300/0,v1:10.1.152.122:6789/0],m3-3101-422=[v2:10.1.155.122:3300/0,v1:10.1.155.122:6789/0],mc-3015-422=[v2:10.1.154.122:3300/0,v1:10.1.154.122:6789/0]}, election epoch 31318, leader 0 dc-3558-422, quorum 0,1,2 dc-3558-422,mc-3015-422,m3-3101-422

# Numeric id isn't recognized
root@dc-3558-422:~# ceph mon ok-to-stop 0
quorum should be preserved (dc-3558-422,m3-3101-422,mc-3015-422) after stopping [0]

# Missing a character
root@dc-3558-422:~# ceph mon ok-to-stop dc-3558-42
quorum should be preserved (dc-3558-422,m3-3101-422,mc-3015-422) after stopping [dc-3558-42]

# all?
root@dc-3558-422:~# ceph mon ok-to-stop all
quorum should be preserved (dc-3558-422,m3-3101-422,mc-3015-422) after stopping [all]

# mds is the same:
root@dc-3558-422:~# ceph mds ok-to-stop all
should be safe to stop [all]

root@dc-3558-422:~# ceph mds ok-to-stop 0
should be safe to stop [0]

The mon and mds ok-to-stop commands are therefore not very safe. "ceph mon ok-to-rm" does seem to validate mon names:

root@dc-3558-422:~# ceph mon ok-to-rm 0
mon.0 does not exist

root@dc-3558-422:~# ceph mon ok-to-rm all
mon.all does not exist

root@dc-3558-422:~# ceph mon ok-to-rm foo
mon.foo does not exist