Retry ssh connections on auth failure.

Some cloud instance types (Fedora for example) create
the ssh user after sshd comes online. This allows
our ssh connection retry loop to handle this scenario
gracefully.

Change-Id: Ie345dea50fc2983112cd2e72826a708583d2712a

nodepool/nodeutils.py

@@ -23,6 +23,7 @@ import logging
 from sshclient import SSHClient
 
 import fakeprovider
+import paramiko
 
 log = logging.getLogger("nodepool.utils")
 
@@ -46,6 +47,10 @@ def ssh_connect(ip, username, connect_kwargs={}, timeout=60):
         try:
             client = SSHClient(ip, username, **connect_kwargs)
             break
+        except paramiko.AuthenticationException, e:
+            # This covers the case where the cloud user is created
+            # after sshd is up (Fedora for example)
+            log.info('Password auth exception. Try number %i...' % count)
         except socket.error, e:
             if e[0] not in [errno.ECONNREFUSED, errno.EHOSTUNREACH]:
                 log.exception('Exception while testing ssh access:')