diff --git a/lib/ssh.py b/lib/ssh.py
index 9e4413a5f145d087ff2e6a182ee659a15d314ad7..bd084870de8da456f01e4a8c3805e4c5a9dfd24a 100644
--- a/lib/ssh.py
+++ b/lib/ssh.py
@@ -53,6 +53,7 @@ def SSHCall(hostname, user, command, batch=True, ask_key=False):
       raise errors.ProgrammerError("SSH call requested conflicting options")
   if ask_key:
     argv.append("-oStrictHostKeyChecking=ask")
+    argv.append("-oHashKnownHosts=no")
   else:
     argv.append("-oStrictHostKeyChecking=yes")
   argv.extend(["%s@%s" % (user, hostname), command])