删除Volume又遇到新的错误，日志开到debug后看到以下的内容。
Clear capabilities
volume volume-4e1817be-9b8c-4834-ad90-baf24ef61775: removing export delete_volume /usr/lib/Python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/volume/manager.py:192
Running cmd (subprocess): sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgt-admin --show execute /usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/utils.py:167
Removing volume: 4e1817be-9b8c-4834-ad90-baf24ef61775
Running cmd (subprocess): sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgt-admin --force --delete iqn.2010-10.org.openstack:volume-4e1817be-9b8c-4834-ad90-baf24ef61775 execute /usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/utils.py:167
Result was 22 execute /usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/utils.py:184
[-] Exception during message handling
Traceback (most recent call last):
File "/usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/openstack/common/rpc/amqp.py", line 276, in _process_data
rval = self.proxy.dispatch(ctxt, version, method, **args)
File "/usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/openstack/common/rpc/dispatcher.py", line 145, in dispatch
return getattr(proxyobj, method)(ctxt, **kwargs)
File "/usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/volume/manager.py", line 206, in delete_volume
{'status': 'error_deleting'})
File "/usr/lib64/python2.6/contextlib.py", line 23, in __exit__
self.gen.next()
File "/usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/volume/manager.py", line 193, in delete_volume
self.driver.remove_export(context, volume_ref)
File "/usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/volume/driver.py", line 474, in remove_export
self.tgtadm.remove_iscsi_target(iscsi_target, 0, volume['id'])
File "/usr/lib/python2.6/site-packages/cinder-2012.2.5-py2.6.egg/cinder/volume/iscsi.py", line 180, in remove_iscsi_target
"id:%(volume_id)s.") % locals())
KeyError: u'volume_id'
虽然最后报的是KeyError的错但实际还是在调用tgt-admin --force --delete <value>出错了，通过tgt-admin -s查看存储节点上的target看到无法删除的target存在链接异常， 类似如下所示，而实际上客户端并不存在这些连接，自然也就无法前面据说的通过客户端来释放了。
Target 28: iqn.2010-10.org.openstack:volume-4b7ee394-0028-4d87-baeb-c0ef4ec134e5
System information:
Driver: iscsi
State: ready
I_T nexus information:
I_T nexus: 121
Initiator: iqn.1994-05.com.RedHat:a3ead9b89ee0
Connection: 0
IP Address: 10.61.2.9
I_T nexus: 138
Initiator: iqn.1994-05.com.redhat:a3ead9b89ee0
Connection: 0
IP Address: 10.61.2.9
I_T nexus: 140
Initiator: iqn.1994-05.com.redhat:a3ead9b89ee0
Connection: 0
IP Address: 10.61.2.9
I_T nexus: 143
Initiator: iqn.1994-05.com.redhat:a3ead9b89ee0
Connection: 0
IP Address: 10.61.2.9
I_T nexus: 147
Initiator: iqn.1994-05.com.redhat:a3ead9b89ee0
Connection: 0
IP Address: 10.61.2.9
I_T nexus: 150
Initiator: iqn.1994-05.com.redhat:a3ead9b89ee0
Connection: 0
IP Address: 10.61.2.9
LUN information:
......
最后我的解决办法是重启tgtd服务，当然正常的service tgtd restart命令是无法重启的因为链接没释放，只能先查到tgtd的pid，然后kill掉并删除锁文件最后重新启动tgtd。