I hit a similar issue, but a bit different, in http://logs.openstack.org/53/76053/16/check/check-grenade-dsvm-partial-ncpu/5a53b07/console.html#_2014-08-18_16_36_31_962 . Seems sometime it will fail to connected, sometime it fail to get the banner. 2014-08-18 16:36:31.962 | 2014-08-18 16:33:03,400 8863 INFO [tempest.common.ssh] Creating ssh connection to '172.24.4.1' as 'cirros' with public key authentication 2014-08-18 16:36:31.962 | 2014-08-18 16:33:03,412 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.962 | 2014-08-18 16:33:03,589 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.962 | 2014-08-18 16:33:03,591 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 1. Retry after 2 seconds. 2014-08-18 16:36:31.962 | 2014-08-18 16:33:06,101 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.962 | 2014-08-18 16:33:06,273 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.962 | 2014-08-18 16:33:06,276 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 2. Retry after 3 seconds. 2014-08-18 16:36:31.962 | 2014-08-18 16:33:09,786 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.962 | 2014-08-18 16:33:09,961 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.963 | 2014-08-18 16:33:09,963 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 3. Retry after 4 seconds. 2014-08-18 16:36:31.963 | 2014-08-18 16:33:14,475 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.963 | 2014-08-18 16:33:14,645 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.963 | 2014-08-18 16:33:14,649 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 4. Retry after 5 seconds. 2014-08-18 16:36:31.963 | 2014-08-18 16:33:20,161 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.963 | 2014-08-18 16:33:20,331 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.963 | 2014-08-18 16:33:20,335 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 5. Retry after 6 seconds. 2014-08-18 16:36:31.963 | 2014-08-18 16:33:26,847 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.963 | 2014-08-18 16:33:27,018 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:27,020 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 6. Retry after 7 seconds. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:34,530 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.964 | 2014-08-18 16:33:34,700 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:34,701 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 7. Retry after 8 seconds. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:43,216 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.964 | 2014-08-18 16:33:43,421 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:43,422 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 8. Retry after 9 seconds. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:52,932 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.964 | 2014-08-18 16:33:53,135 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.964 | 2014-08-18 16:33:53,136 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 9. Retry after 10 seconds. 2014-08-18 16:36:31.964 | 2014-08-18 16:34:03,645 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.965 | 2014-08-18 16:34:03,814 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.965 | 2014-08-18 16:34:03,815 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 10. Retry after 11 seconds. 2014-08-18 16:36:31.965 | 2014-08-18 16:34:15,332 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.965 | 2014-08-18 16:34:15,504 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.965 | 2014-08-18 16:34:15,505 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 11. Retry after 12 seconds. 2014-08-18 16:36:31.965 | 2014-08-18 16:34:28,019 8863 ERROR [paramiko.transport] Exception: Error reading SSH protocol banner 2014-08-18 16:36:31.965 | 2014-08-18 16:34:28,021 8863 ERROR [paramiko.transport] Traceback (most recent call last): 2014-08-18 16:36:31.965 | 2014-08-18 16:34:28,021 8863 ERROR [paramiko.transport] File "/usr/local/lib/python2.7/dist-packages/paramiko/transport.py", line 1412, in run 2014-08-18 16:36:31.965 | 2014-08-18 16:34:28,021 8863 ERROR [paramiko.transport] self._check_banner() 2014-08-18 16:36:31.965 | 2014-08-18 16:34:28,021 8863 ERROR [paramiko.transport] File "/usr/local/lib/python2.7/dist-packages/paramiko/transport.py", line 1539, in _check_banner 2014-08-18 16:36:31.965 | 2014-08-18 16:34:28,021 8863 ERROR [paramiko.transport] raise SSHException('Error reading SSH protocol banner' + str(e)) 2014-08-18 16:36:31.966 | 2014-08-18 16:34:28,022 8863 ERROR [paramiko.transport] SSHException: Error reading SSH protocol banner 2014-08-18 16:36:31.966 | 2014-08-18 16:34:28,022 8863 ERROR [paramiko.transport] 2014-08-18 16:36:31.966 | 2014-08-18 16:34:28,026 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Error reading SSH protocol banner). Number attempts: 12. Retry after 13 seconds. 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,538 8863 ERROR [paramiko.transport] Exception: Error reading SSH protocol banner 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,539 8863 ERROR [paramiko.transport] Traceback (most recent call last): 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,539 8863 ERROR [paramiko.transport] File "/usr/local/lib/python2.7/dist-packages/paramiko/transport.py", line 1412, in run 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,539 8863 ERROR [paramiko.transport] self._check_banner() 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,539 8863 ERROR [paramiko.transport] File "/usr/local/lib/python2.7/dist-packages/paramiko/transport.py", line 1539, in _check_banner 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,539 8863 ERROR [paramiko.transport] raise SSHException('Error reading SSH protocol banner' + str(e)) 2014-08-18 16:36:31.966 | 2014-08-18 16:34:41,540 8863 ERROR [paramiko.transport] SSHException: Error reading SSH protocol banner 2014-08-18 16:36:31.967 | 2014-08-18 16:34:41,540 8863 ERROR [paramiko.transport] 2014-08-18 16:36:31.967 | 2014-08-18 16:34:41,542 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Error reading SSH protocol banner). Number attempts: 13. Retry after 14 seconds. 2014-08-18 16:36:31.967 | 2014-08-18 16:34:56,055 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.967 | 2014-08-18 16:34:56,228 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.967 | 2014-08-18 16:34:56,228 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 14. Retry after 15 seconds. 2014-08-18 16:36:31.967 | 2014-08-18 16:35:11,751 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.967 | 2014-08-18 16:35:11,918 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.967 | 2014-08-18 16:35:11,919 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 15. Retry after 16 seconds. 2014-08-18 16:36:31.967 | 2014-08-18 16:35:28,442 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.967 | 2014-08-18 16:35:28,613 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.967 | 2014-08-18 16:35:28,618 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 16. Retry after 17 seconds. 2014-08-18 16:36:31.968 | 2014-08-18 16:35:46,142 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.968 | 2014-08-18 16:35:46,310 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.968 | 2014-08-18 16:35:46,312 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 17. Retry after 18 seconds. 2014-08-18 16:36:31.968 | 2014-08-18 16:36:04,837 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.968 | 2014-08-18 16:36:05,006 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.968 | 2014-08-18 16:36:05,008 8863 WARNING [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 (Authentication failed.). Number attempts: 18. Retry after 19 seconds. 2014-08-18 16:36:31.968 | 2014-08-18 16:36:24,523 8863 INFO [paramiko.transport] Connected (version 2.0, client OpenSSH_6.6.1p1) 2014-08-18 16:36:31.968 | 2014-08-18 16:36:24,697 8863 INFO [paramiko.transport] Authentication (publickey) failed. 2014-08-18 16:36:31.968 | 2014-08-18 16:36:24,700 8863 ERROR [tempest.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.4.1 after 18 attempts 2014-08-18 16:36:31.968 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh Traceback (most recent call last): 2014-08-18 16:36:31.968 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh File "tempest/common/ssh.py", line 76, in _get_ssh_connection 2014-08-18 16:36:31.969 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh timeout=self.channel_timeout, pkey=self.pkey) 2014-08-18 16:36:31.969 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh File "/usr/local/lib/python2.7/dist-packages/paramiko/client.py", line 273, in connect 2014-08-18 16:36:31.969 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh self._auth(username, password, pkey, key_filenames, allow_agent, look_for_keys) 2014-08-18 16:36:31.969 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh File "/usr/local/lib/python2.7/dist-packages/paramiko/client.py", line 456, in _auth 2014-08-18 16:36:31.969 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh raise saved_exception 2014-08-18 16:36:31.969 | 2014-08-18 16:36:24.700 8863 TRACE tempest.common.ssh AuthenticationException: Authentication failed.