HBASE-4654 [replication] Add a check to make sure we don't replicate to ourselves (Demai)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1541279 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSource.java

@@ -212,6 +212,12 @@ public class ReplicationSource extends Thread
     // resetting to 1 to reuse later
     sleepMultiplier = 1;
 
+    // In rare case, zookeeper setting may be messed up. That leads to the incorrect
+    // peerClusterId value, which is the same as the source clusterId
+    if (clusterId.equals(peerClusterId)) {
+      this.terminate("ClusterId " + clusterId + " is replicating to itself: peerClusterId "
+          + peerClusterId);
+    }
     LOG.info("Replicating "+clusterId + " -> " + peerClusterId);
 
     // If this is recovered, the queue is already full and the first log