现象：

Centos7

opstack block1创建卷正常

挂载到虚拟机实例，dashboard无报错，连接到失败，显示空白

查看volume.log报错：

2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher [req-70a7325b-cead-4dd7-a80a-23425552d29d e802515855974f019d7a3bcfcf77c259 bcf99fcaa2bb42778972c1f0959f6cbf - - -] Exception during message handling: Unexpected error while running command.
Command: sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgtadm --lld iscsi --op show --mode target
Exit code: 96
Stdout: u''
Stderr: u'/usr/bin/cinder-rootwrap: Executable not found: tgtadm (filter match = tgtadm)\n'
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher Traceback (most recent call last):
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher incoming.message))
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _dispatch
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher return self._do_dispatch(endpoint, method, ctxt, args)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _do_dispatch
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher result = func(ctxt, **new_args)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/cinder/volume/manager.py", line 1442, in initialize_connection
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher volume, connector)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/lvm.py", line 760, in create_export
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher volume_path)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/cinder/volume/targets/iscsi.py", line 210, in create_export
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher **portals_config)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/cinder/volume/targets/tgt.py", line 140, in create_iscsi_target
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher run_as_root=True)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 148, in execute
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher return processutils.execute(*cmd, **kwargs)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher File "/usr/lib/python2.7/site-packages/oslo_concurrency/processutils.py", line 389, in execute
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher cmd=sanitized_cmd)
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher ProcessExecutionError: Unexpected error while running command.
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher Command: sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgtadm --lld iscsi --op show --mode target
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher Exit code: 96
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher Stdout: u''
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher Stderr: u'/usr/bin/cinder-rootwrap: Executable not found: tgtadm (filter match = tgtadm)\n'
2017-02-28 11:25:39.214 2989 ERROR oslo_messaging.rpc.dispatcher
2017-02-28 11:25:39.226 2989 ERROR oslo_messaging._drivers.common [req-70a7325b-cead-4dd7-a80a-23425552d29d e802515855974f019d7a3bcfcf77c259 bcf99fcaa2bb42778972c1f0959f6cbf - - -] Returning exception Unexpected error while running command.
Command: sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgtadm --lld iscsi --op show --mode target
Exit code: 96
Stdout: u''
Stderr: u'/usr/bin/cinder-rootwrap: Executable not found: tgtadm (filter match = tgtadm)\n' to caller
2017-02-28 11:25:39.227 2989 ERROR oslo_messaging._drivers.common [req-70a7325b-cead-4dd7-a80a-23425552d29d e802515855974f019d7a3bcfcf77c259 bcf99fcaa2bb42778972c1f0959f6cbf - - -] ['Traceback (most recent call last):\n', ' File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply\n incoming.message))\n', ' File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _dispatch\n return self._do_dispatch(endpoint, method, ctxt, args)\n', ' File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _do_dispatch\n result = func(ctxt, **new_args)\n', ' File "/usr/lib/python2.7/site-packages/cinder/volume/manager.py", line 1442, in initialize_connection\n volume, connector)\n', ' File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/lvm.py", line 760, in create_export\n volume_path)\n', ' File "/usr/lib/python2.7/site-packages/cinder/volume/targets/iscsi.py", line 210, in create_export\n **portals_config)\n', ' File "/usr/lib/python2.7/site-packages/cinder/volume/targets/tgt.py", line 140, in create_iscsi_target\n run_as_root=True)\n', ' File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 148, in execute\n return processutils.execute(*cmd, **kwargs)\n', ' File "/usr/lib/python2.7/site-packages/oslo_concurrency/processutils.py", line 389, in execute\n cmd=sanitized_cmd)\n', "ProcessExecutionError: Unexpected error while running command.\nCommand: sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgtadm --lld iscsi --op show --mode target\nExit code: 96\nStdout: u''\nStderr: u'/usr/bin/cinder-rootwrap: Executable not found: tgtadm (filter match = tgtadm)\\n'\n"]
2017-02-28 11:25:39.897 2989 INFO cinder.volume.manager [req-98f2f209-3f2e-450b-be11-be1008be529e e802515855974f019d7a3bcfcf77c259 bcf99fcaa2bb42778972c1f0959f6cbf - - -] Terminate volume connection completed successfully.
2017-02-28 11:27:48.642 2989 ERROR oslo_messaging.rpc.dispatcher [req-1f5b2425-6e2d-4781-89d5-e6dd291c57c4 e802515855974f019d7a3bcfcf77c259 bcf99fcaa2bb42778972c1f0959f6cbf - - -] Exception during message handling: Unexpected error while running command.
Command: sudo cinder-rootwrap /etc/cinder/rootwrap.conf tgtadm --lld iscsi --op show --mode target
Exit code: 96
Stdout: u''
Stderr: u'/usr/bin/cinder-rootwrap: Executable not found: tgtadm (filter match = tgtadm)\n'

解决处理：

官方文档的坑，安装cinder的cinder.conf中没有[lvm]标签，需要手动加入[lvm]标签

[lvm]
volume_driver = cinder.volume.drivers.lvm.LVMVolumeDriver 
volume_group = cinder-volumes 
iscsi_protocol = iscsi 
iscsi_helper = lioadm