From ff8c2fcac0324a1cfa5608062e0e5fc263cb8160 Mon Sep 17 00:00:00 2001
From: Elliott Clark <eclark@apache.org>
Date: Wed, 22 Jun 2016 15:40:28 -0700
Subject: [PATCH] HBASE-16087 Replication shouldn't start on a master if if
 only hosts system tables

---
 .../master/balancer/BaseLoadBalancer.java      | 13 +++++++++++++
 .../hbase/regionserver/HRegionServer.java      | 18 ++++++++++++------
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
index 15c0fc2e50e..0a61839f9c6 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
@@ -1001,6 +1001,19 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
     return tables != null && tables.length > 0;
   }
 
+  public static boolean userTablesOnMaster(Configuration conf) {
+    String[] tables = getTablesOnMaster(conf);
+    if (tables == null || tables.length == 0) {
+      return false;
+    }
+    for (String tn:tables) {
+      if (!tn.startsWith("hbase:")) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   @Override
   public void setConf(Configuration conf) {
     setSlop(conf);
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
index 4d6b9b8b576..5e7ce5a5da1 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
@@ -107,6 +107,7 @@ import org.apache.hadoop.hbase.ipc.ServerRpcController;
 import org.apache.hadoop.hbase.master.HMaster;
 import org.apache.hadoop.hbase.master.RegionState.State;
 import org.apache.hadoop.hbase.master.TableLockManager;
+import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer;
 import org.apache.hadoop.hbase.procedure.RegionServerProcedureManagerHost;
 import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.protobuf.RequestConverter;
@@ -447,7 +448,7 @@ public class HRegionServer extends HasThread implements
   private RegionServerCoprocessorHost rsHost;
 
   private RegionServerProcedureManagerHost rspmHost;
-  
+
   private RegionServerQuotaManager rsQuotaManager;
 
   // Table level lock manager for locking for region operations
@@ -873,7 +874,7 @@ public class HRegionServer extends HasThread implements
 
     // Setup the Quota Manager
     rsQuotaManager = new RegionServerQuotaManager(this);
-    
+
     // Setup RPC client for master communication
     rpcClient = RpcClientFactory.createClient(conf, clusterId, new InetSocketAddress(
         rpcServices.isa.getAddress(), 0), clusterConnection.getConnectionMetrics());
@@ -942,7 +943,7 @@ public class HRegionServer extends HasThread implements
         // since the server is ready to run
         rspmHost.start();
       }
-      
+
       // Start the Quota Manager
       if (this.rsQuotaManager != null) {
         rsQuotaManager.start(getRpcServer().getScheduler());
@@ -1036,7 +1037,7 @@ public class HRegionServer extends HasThread implements
     if (rsQuotaManager != null) {
       rsQuotaManager.stop();
     }
-    
+
     // Stop the snapshot and other procedure handlers, forcefully killing all running tasks
     if (rspmHost != null) {
       rspmHost.stop(this.abortRequested || this.killed);
@@ -2600,7 +2601,7 @@ public class HRegionServer extends HasThread implements
   public ChoreService getChoreService() {
     return choreService;
   }
-  
+
   @Override
   public RegionServerQuotaManager getRegionServerQuotaManager() {
     return rsQuotaManager;
@@ -2622,6 +2623,11 @@ public class HRegionServer extends HasThread implements
       return;
     }
 
+    if ((server instanceof HMaster) &&
+        (!BaseLoadBalancer.userTablesOnMaster(conf))) {
+      return;
+    }
+
     // read in the name of the source replication class from the config file.
     String sourceClassname = conf.get(HConstants.REPLICATION_SOURCE_SERVICE_CLASSNAME,
                                HConstants.REPLICATION_SERVICE_CLASSNAME_DEFAULT);
@@ -2723,7 +2729,7 @@ public class HRegionServer extends HasThread implements
      }
      return tableRegions;
    }
-  
+
   /**
    * Gets the online tables in this RS.
    * This method looks at the in-memory onlineRegions.