add extra ssh options to prevent host key changed errors

TES/tes/sshwrapper/__init__.py

@@ -91,6 +91,8 @@ class Ssh:
 
         if mode is None:
             sshcmd = ["ssh", '-o', 'StrictHostKeyChecking=no',
+                      '-o', 'UserKnownHostsFile=/dev/null',
+                      '-o', 'UpdateHostsFile=no',
                       "-S", ctrlsocket,
                       "-M", '-o', 'ControlPersist=10m',
                       '-p', sshport, '-N','-l', user, host]
@@ -169,6 +171,9 @@ class Ssh:
         Ssh.validate_hostname(host)
         ctrlsocket = Ssh.get_ctrl_master_socket(sess, host, user, sshport)
         exec_p = subprocess.Popen(['sftp', '-b', '-','-o', 'Stricthostkeychecking=no',
+                                    
+                                   '-o', 'UserKnownHostsFile=/dev/null',
+                                   '-o', 'UpdateHostsFile=no',
                                    '-P', sshport, '-o', 'ControlPath={}'.format(ctrlsocket),
                                    '{}@{}'.format(user, host)],
                                   stdout=subprocess.PIPE, stderr=subprocess.PIPE,
@@ -217,6 +222,8 @@ class Ssh:
         if (changepath is None or changepath == ""):
             changepath="."
         exec_p = subprocess.Popen(['sftp', '-b', '-','-o', 'Stricthostkeychecking=no',
+                                   '-o', 'UserKnownHostsFile=/dev/null',
+                                   '-o', 'UpdateHostsFile=no',
                                    '-P', sshport, '-o', 'ControlPath={}'.format(ctrlsocket),
                                    '{}@{}'.format(user, host)],
                                   stdout=subprocess.PIPE, stderr=subprocess.PIPE,
@@ -272,18 +279,22 @@ class Ssh:
         if bastion == None:
             # we are executing this command on the login node, so no more magic is needed
             sshcmd = ['ssh', '-o', 'Stricthostkeychecking=no', 
+                      '-o', 'UserKnownHostsFile=/dev/null',
+                      '-o', 'UpdateHostsFile=no',
                       '-S', ctrlsocket, '-p', sshport,
                       '-l', user, host, cmd]
         else:
             # we are executing on a node (e.g. a compute/batch node) using a bastion (e.g. login node)
             # at the moment I'll assume the ssh port for the batch host is the same as the ssh port for the bastion/login host
-            proxycmd = "ssh -o Stricthostkeychecking=no {user}@{bastion} -W {host}:{sshport} -S {ctrlsocket}".format(
+            proxycmd = "ssh -o UserKnownHostsFile=/dev/null -o UpdateHostsFile=no -o Stricthostkeychecking=no {user}@{bastion} -W {host}:{sshport} -S {ctrlsocket}".format(
                 user=user, host=host,
                 ctrlsocket=ctrlsocket,
                 sshport=sshport,
                 bastion=bastion)
-            sshcmd = ['ssh', '-o', 'Stricthostkeychecking=no',
+            sshcmd = ['ssh', '-o', 'Stricthostkeychecking=no',  
                       '-o', "ProxyCommand={}".format(proxycmd),
+                      '-o', 'UserKnownHostsFile=/dev/null',
+                      '-o', 'UpdateHostsFile=no',
                       '-p', bastionsshport, '-l', user, bastion, cmd]
         exec_p = subprocess.Popen(sshcmd,stdout=subprocess.PIPE,stderr=subprocess.PIPE,stdin=subprocess.PIPE,env=env)
 
@@ -327,6 +338,8 @@ class Ssh:
             # Can we use the existing control master connection and just add a
             # port forward to the batch node
             sshcmd = ['ssh', '-o', 'Stricthostkeychecking=no', '-N',
+                      '-o', 'UserKnownHostsFile=/dev/null',
+                      '-o', 'UpdateHostsFile=no',
                       '-L', '{localport}:{batchhost}:{port}'.
                       format(port=port, localport=localport, batchhost=batchhost),
                       '-O', 'forward', '-S', ctrlsocket,
@@ -335,13 +348,15 @@ class Ssh:
             # Create an ssh tunnel to the batch node using a proxycommand.
             # The proxy command should utilise
             # the existing control master connection
-            proxycmd = "ssh -o Stricthostkeychecking=no {user}@{host} -W {batchhost}:22 -S {ctrlsocket}".format(
+            proxycmd = "ssh -o UserKnownHostsFile=/dev/null -o UpdateHostsFile=no -o Stricthostkeychecking=no {user}@{host} -W {batchhost}:22 -S {ctrlsocket}".format(
                 user=user, host=host,
                 ctrlsocket=ctrlsocket,
                 batchhost=batchhost)
             sshcmd = ['ssh', '-o', 'Stricthostkeychecking=no', '-N',
                       '-L', '{localport}:localhost:{port}'.
                       format(port=port, localport=localport),
+                      '-o', 'UserKnownHostsFile=/dev/null',
+                      '-o', 'UpdateHostsFile=no',
                       '-o', "ProxyCommand={}".format(proxycmd),
                       '-p', sshport, '-l', user, batchhost]