在一个使用的环境发现两个ceph的rbd删除不了，发现两个rbd都是由于残留了watch的信息。在此记录处理过程。
处理方法
[root@node-2 ~]# rbd rm compute/2d05517a-8670-4cce-b39d-709e055381d6_disk 2018-06-11 13:19:14.787750 7fd05853bd80 -1 librbd: cannot obtain exclusive lock - not removing Removing image: 0% complete...failed. rbd: error: image still has watchers This means the image is still open or the client using it crashed. Try again after closing/unmapping it or waiting 30s for the crashed client to timeout.
查看rbd 残留的watch信息
[root@node-2 ~]# rbd status compute/2d05517a-8670-4cce-b39d-709e055381d6_disk Watchers: watcher=192.168.55.2:0/2900899764 client.14844 cookie=139644428642944
将该残留的watch信息添加到osd的黑名单，再查看watch是否存在。
[root@node-2 ~]# ceph osd blacklist add 192.168.55.2:0/2900899764 blacklisting 192.168.55.2:0/2900899764 until 2018-06-11 14:25:31.027420 (3600 sec)
[root@node-2 ~]# rbd status compute/2d05517a-8670-4cce-b39d-709e055381d6_disk Watchers: none
删除rbd
[root@node-2 ~]# rbd rm compute/2d05517a-8670-4cce-b39d-709e055381d6_disk Removing image: 100% complete...done.