Merge "Have nodepool scan as many ssh host keys as possible"

nodepool/nodeutils.py

@@ -73,41 +73,79 @@ def nodescan(ip, port=22, timeout=60, gather_hostkeys=True):
 
     keys = []
     key = None
+    # First we wait for the sshd to be listening
     for count in iterate_timeout(
             timeout, exceptions.ConnectionTimeoutException,
             "connection to %s on port %s" % (ip, port)):
         sock = None
-        t = None
         try:
             sock = socket.socket(family, socket.SOCK_STREAM)
             sock.settimeout(10)
             sock.connect(sockaddr)
-            if gather_hostkeys:
-                t = paramiko.transport.Transport(sock)
-                t.start_client(timeout=timeout)
-                key = t.get_remote_server_key()
             break
         except socket.error as e:
             if e.errno not in [errno.ECONNREFUSED, errno.EHOSTUNREACH, None]:
                 log.exception(
                     'Exception connecting to %s on port %s:' % (ip, port))
-        except Exception as e:
+        except Exception:
-            log.exception("ssh-keyscan failure: %s", e)
+            log.exception("ssh socket connection failure")
         finally:
-            try:
-                if t:
-                    t.close()
-            except Exception as e:
-                log.exception('Exception closing paramiko: %s', e)
             try:
                 if sock:
                     sock.close()
-            except Exception as e:
+            except Exception:
-                log.exception('Exception closing socket: %s', e)
+                log.exception('Exception closing socket')
+            sock = None
+    if gather_hostkeys:
+        sock = None
+        t = None
+        key_index = 0
+        # Now we gather hostkeys
+        while key_index >= 0:
+            try:
+                sock = socket.socket(family, socket.SOCK_STREAM)
+                # Do this early so that we don't trigger exceptions
+                t = paramiko.transport.Transport(sock)
+                opts = paramiko.transport.SecurityOptions(t)
+                # We use each supported key type in turn to ensure we get
+                # back that specific host key type.
+                key_types = opts.key_types
+                opts.key_types = [key_types[key_index]]
+                key_index += 1
+                if key_index >= len(key_types):
+                    key_index = -1
 
-    # Paramiko, at this time, seems to return only the ssh-rsa key, so
+                sock.settimeout(10)
-    # only the single key is placed into the list.
+                sock.connect(sockaddr)
-    if key:
+                t.start_client(timeout=timeout)
-        keys.append("%s %s" % (key.get_name(), key.get_base64()))
+                key = t.get_remote_server_key()
+                if key:
+                    keys.append("%s %s" % (key.get_name(), key.get_base64()))
+                    log.debug('Added ssh host key: %s', key.get_name())
+            except paramiko.SSHException as e:
+                msg = str(e)
+                if 'no acceptable host key' not in msg:
+                    # We expect some host keys to not be valid when scanning
+                    # only log if the error isn't due to mismatched host key
+                    # types.
+                    log.exception("ssh-keyscan failure")
+            except socket.error:
+                log.exception(
+                    'Exception connecting to %s on port %s:' % (ip, port))
+            except Exception:
+                log.exception("ssh-keyscan failure")
+            finally:
+                try:
+                    if t:
+                        t.close()
+                except Exception:
+                    log.exception('Exception closing paramiko')
+                t = None
+                try:
+                    if sock:
+                        sock.close()
+                except Exception:
+                    log.exception('Exception closing socket')
+                sock = None
 
     return keys