问题描述：
在CentOS7.2上运行Fabric报下面的错误：
File "/usr/lib/python2.7/site-packages/fabric/network.py", line 109, in __getitem__ self.connect(key)
File "/usr/lib/python2.7/site-packages/fabric/network.py", line 101, in connect self[key] = connect(user, host, port, sock)
File "/usr/lib/python2.7/site-packages/fabric/network.py", line 354, in connect sock=sock
File "/usr/lib/python2.7/site-packages/paramiko/client.py", line 338, in connect t.start_client()
File "/usr/lib/python2.7/site-packages/paramiko/transport.py", line 492, in start_client raise e
ValueError: CTR mode needs counter parameter, not IV
解决办法：
yum install -y python2-paramiko