Prevent master failover if we have wrong data

If we don't actually know the current master (as determined via voting),
we prevent the failover.

The patch also changes some messages (capitalization, typos).

Reviewed-by: ultrotter

lib/bootstrap.py

@@ -352,20 +352,34 @@ def MasterFailover():
 
   new_master = utils.HostInfo().name
   old_master = cfg.GetMasterNode()
+  node_list = cfg.GetNodeList()
 
   if old_master == new_master:
     raise errors.OpPrereqError("This commands must be run on the node"
                                " where you want the new master to be."
                                " %s is already the master" %
                                old_master)
+
+  vote_list = GatherMasterVotes(node_list)
+
+  if vote_list:
+    voted_master = vote_list[0][0]
+    if voted_master is None:
+      raise errors.OpPrereqError("Cluster is inconsistent, most nodes did not"
+                                 " respond.")
+    elif voted_master != old_master:
+      raise errors.OpPrereqError("I have wrong configuration, I believe the"
+                                 " master is %s but the other nodes voted for"
+                                 " %s. Please resync the configuration of"
+                                 " this node." % (old_master, voted_master))
   # end checks
 
   rcode = 0
 
-  logging.info("setting master to %s, old master: %s", new_master, old_master)
+  logging.info("Setting master to %s, old master: %s", new_master, old_master)
 
   if not RpcRunner.call_node_stop_master(old_master, True):
-    logging.error("could disable the master role on the old master"
+    logging.error("Could not disable the master role on the old master"
                  " %s, please disable manually", old_master)
 
   cfg.SetMasterNode(new_master)
@@ -375,11 +389,12 @@ def MasterFailover():
 
   if not RpcRunner.call_upload_file(cfg.GetNodeList(),
                                     constants.CLUSTER_CONF_FILE):
-    logging.error("could not distribute the new simple store master file"
+    logging.error("Could not distribute the new configuration"
                   " to the other nodes, please check.")
 
+
   if not RpcRunner.call_node_start_master(new_master, True):
-    logging.error("could not start the master role on the new master"
+    logging.error("Could not start the master role on the new master"
                   " %s, please check", new_master)
     rcode = 1