HBASE-10923 Control where to put meta region

hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java

@@ -63,25 +63,6 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
   private static final int MIN_SERVER_BALANCE = 2;
   private volatile boolean stopped = false;
 
-  protected static final Set<String> TABLES_ON_MASTER = new HashSet<String>();
-
-  /**
-   * Regions of these tables will be put on the master regionserver by default.
-   */
-  static {
-    TABLES_ON_MASTER.add(AccessControlLists.ACL_TABLE_NAME.getNameAsString());
-    TABLES_ON_MASTER.add(TableName.NAMESPACE_TABLE_NAME.getNameAsString());
-    TABLES_ON_MASTER.add(TableName.META_TABLE_NAME.getNameAsString());
-  }
-
-  /**
-   * Check if a region belongs to some small system table.
-   * If so, it may be expected to be put on the master regionserver.
-   */
-  protected static boolean shouldBeOnMaster(HRegionInfo region) {
-    return TABLES_ON_MASTER.contains(region.getTable().getNameAsString());
-  }
-
   /**
    * An efficient array based implementation similar to ClusterState for keeping
    * the status of the cluster in terms of region assignment and distribution.
@@ -89,6 +70,7 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
    */
   protected static class Cluster {
     ServerName masterServerName;
+    Set<String> tablesOnMaster;
     ServerName[] servers;
     ArrayList<String> tables;
     HRegionInfo[] regions;
@@ -123,8 +105,10 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
         Map<ServerName, List<HRegionInfo>> clusterState,
         Map<String, Deque<RegionLoad>> loads,
         RegionLocationFinder regionFinder,
-        Collection<ServerName> backupMasters) {
+        Collection<ServerName> backupMasters,
+        Set<String> tablesOnMaster) {
 
+      this.tablesOnMaster = tablesOnMaster;
       this.masterServerName = masterServerName;
       serversToIndex = new HashMap<String, Integer>();
       tablesToIndex = new HashMap<String, Integer>();
@@ -133,7 +117,6 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
       //TODO: We should get the list of tables from master
       tables = new ArrayList<String>();
 
-
       numRegions = 0;
 
       int serverIndex = 0;
@@ -380,6 +363,11 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
       return activeMasterIndex == server;
     }
 
+    boolean shouldBeOnMaster(HRegionInfo region) {
+      return tablesOnMaster != null && tablesOnMaster.contains(
+        region.getTable().getNameAsString());
+    }
+
     private Comparator<Integer> numRegionsComparator = new Comparator<Integer>() {
       @Override
       public int compare(Integer integer, Integer integer2) {
@@ -448,6 +436,12 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
     "hbase.balancer.activeMasterWeight";
   private static final int DEFAULT_ACTIVE_MASTER_WEIGHT = 200;
 
+  // Regions of these tables are put on the master by default.
+  private static final String[] DEFAULT_TABLES_ON_MASTER =
+    new String[] {AccessControlLists.ACL_TABLE_NAME.getNameAsString(),
+      TableName.NAMESPACE_TABLE_NAME.getNameAsString(),
+      TableName.META_TABLE_NAME.getNameAsString()};
+
   protected int activeMasterWeight;
   protected int backupMasterWeight;
 
@@ -456,6 +450,7 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
   protected final Set<ServerName> excludedServers =
     Collections.synchronizedSet(new HashSet<ServerName>());
 
+  protected final Set<String> tablesOnMaster = new HashSet<String>();
   protected final MetricsBalancer metricsBalancer = new MetricsBalancer();
   protected ClusterStatus clusterStatus = null;
   protected ServerName masterServerName;
@@ -478,6 +473,13 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
         + BACKUP_MASTER_WEIGHT_KEY + " is " + backupMasterWeight
         + "(<1)");
     }
+    String[] tables = conf.getStrings(
+      "hbase.balancer.tablesOnMaster", DEFAULT_TABLES_ON_MASTER);
+    if (tables != null) {
+      for (String table: tables) {
+        tablesOnMaster.add(table);
+      }
+    }
   }
 
   protected void setSlop(Configuration conf) {
@@ -500,6 +502,15 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
       }
     }
   }
+
+  /**
+   * Check if a region belongs to some small system table.
+   * If so, it may be expected to be put on the master regionserver.
+   */
+  protected boolean shouldBeOnMaster(HRegionInfo region) {
+    return tablesOnMaster.contains(region.getTable().getNameAsString());
+  }
+
   /**
    * Balance the regions that should be on master regionserver.
    */

hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java

@@ -202,8 +202,8 @@ public class StochasticLoadBalancer extends BaseLoadBalancer {
     long startTime = EnvironmentEdgeManager.currentTimeMillis();
 
     // Keep track of servers to iterate through them.
-    Cluster cluster = new Cluster(masterServerName,
-      clusterState, loads, regionFinder, getBackupMasters());
+    Cluster cluster = new Cluster(masterServerName, clusterState,
+      loads, regionFinder, getBackupMasters(), tablesOnMaster);
     double currentCost = computeCost(cluster, Double.MAX_VALUE);
 
     double initCost = currentCost;

hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/BalancerTestBase.java

@@ -165,7 +165,7 @@ public class BalancerTestBase {
 
   protected BaseLoadBalancer.Cluster mockCluster(int[] mockCluster) {
     return new BaseLoadBalancer.Cluster(null,
-      mockClusterServers(mockCluster, -1), null, null, null);
+      mockClusterServers(mockCluster, -1), null, null, null, null);
   }
 
   protected Map<ServerName, List<HRegionInfo>> mockClusterServers(int[] mockCluster, int numTables) {

hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestBaseLoadBalancer.java

@@ -289,7 +289,7 @@ public class TestBaseLoadBalancer extends BalancerTestBase {
     assignRegions(regions, oldServers, clusterState);
 
     // should not throw exception:
-    BaseLoadBalancer.Cluster cluster = new Cluster(null, clusterState, null, null, null);
+    BaseLoadBalancer.Cluster cluster = new Cluster(null, clusterState, null, null, null, null);
     assertEquals(101 + 9, cluster.numRegions);
     assertEquals(10, cluster.numServers); // only 10 servers because they share the same host + port
   }
@@ -331,7 +331,7 @@ public class TestBaseLoadBalancer extends BalancerTestBase {
     when(locationFinder.getTopBlockLocations(regions.get(43))).thenReturn(
       Lists.newArrayList(ServerName.valueOf("foo", 0, 0))); // this server does not exists in clusterStatus
 
-    BaseLoadBalancer.Cluster cluster = new Cluster(null, clusterState, null, locationFinder, null);
+    BaseLoadBalancer.Cluster cluster = new Cluster(null, clusterState, null, locationFinder, null, null);
 
     int r0 = ArrayUtils.indexOf(cluster.regions, regions.get(0)); // this is ok, it is just a test
     int r1 = ArrayUtils.indexOf(cluster.regions, regions.get(1));