Ceph RBD Watchers shows nothing but I can’t delete it!

So this issue is pretty interesting.

In my situation I had deleted the /dev/rbdX device so I couldn’t unmap the volume.  But because it was still mapped the rbd header was locked.

I was able to determine this with:


[root@ceph0-mon0 ~]# rbd info  volume-480ee746-d9d1-4625-833c-8573e2cb7a39 -p cinder-capacity-vol.prd.cin1

rbd image ‘volume-480ee746-d9d1-4625-833c-8573e2cb7a39’:

size 145 GB in 37120 objects

order 22 (4096 kB objects)

block_name_prefix: rbd_data.75476776dfc3c0

format: 2

features: layering, striping


stripe unit: 4096 kB

stripe count: 1

So then I looked at the RBD header:

[root@ceph0-mon0 ~]# rados -p cinder-capacity-vol.prd.cin1 listwatchers rbd_header.75476776dfc3c0

watcher= client.7590353 cookie=7

watcher= client.7590353 cookie=8

watcher= client.7590353 cookie=9

So This lead me to the host in question.

root@osc-1001> rbd showmapped

id pool                         image                                       snap device    

0  cinder-capacity-vol.prd.cin1 volume-22567261-a438-4334-8a49-412193e1cd2f –    /dev/rbd0

1  cinder-capacity-vol.prd.cin1 volume-22567261-a438-4334-8a49-412193e1cd2f –    /dev/rbd1

2  cinder-capacity-vol.prd.cin1 volume-480ee746-d9d1-4625-833c-8573e2cb7a39 –    /dev/rbd2

3  cinder-capacity-vol.prd.cin1 volume-480ee746-d9d1-4625-833c-8573e2cb7a39 –    /dev/rbd3

4  cinder-capacity-vol.prd.cin1 volume-480ee746-d9d1-4625-833c-8573e2cb7a39 –    /dev/rbd4

Sure enough those were mapped.  But none of the /dev/rbdX devices exists.. so I cannot unmap them.

The only solution I have found is to reboot the host.

— Update:  http://tracker.ceph.com/issues/2654


Looks like this is fixed on 3.4… My kernel is 3.10.  SOL!