HBASE-12559 Provide LoadBalancer with online configuration capability

hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java

@@ -1253,6 +1253,12 @@ public interface Admin extends Abortable, Closeable {
    */
   CoprocessorRpcChannel coprocessorService(ServerName sn);
 
+  /**
+   * Update the configuration and trigger an online config change
+   * on the master
+   * @throws IOException
+   */
+  void updateMasterConfiguration() throws IOException;
 
   /**
    * Update the configuration and trigger an online config change

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionManager.java

@@ -162,6 +162,8 @@ import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.TruncateTableRequ
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.TruncateTableResponse;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UnassignRegionRequest;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UnassignRegionResponse;
+import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UpdateMasterConfigurationRequest;
+import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UpdateMasterConfigurationResponse;
 import org.apache.hadoop.hbase.regionserver.RegionServerStoppedException;
 import org.apache.hadoop.hbase.security.User;
 import org.apache.hadoop.hbase.security.UserProvider;
@@ -1714,6 +1716,12 @@ class ConnectionManager {
           return stub.addColumn(controller, request);
         }
 
+        @Override
+        public UpdateMasterConfigurationResponse updateMasterConfiguration(RpcController controller,
+            UpdateMasterConfigurationRequest request) throws ServiceException {
+          return stub.updateMasterConfiguration(controller, request);
+        }
+
         @Override
         public DeleteColumnResponse deleteColumn(RpcController controller,
             DeleteColumnRequest request)

hbase-client/src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java

@@ -128,6 +128,7 @@ import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.SnapshotResponse;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.StopMasterRequest;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.TruncateTableRequest;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UnassignRegionRequest;
+import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UpdateMasterConfigurationRequest;
 import org.apache.hadoop.hbase.quotas.QuotaFilter;
 import org.apache.hadoop.hbase.quotas.QuotaRetriever;
 import org.apache.hadoop.hbase.quotas.QuotaSettings;
@@ -3719,6 +3720,16 @@ public class HBaseAdmin implements Admin {
     return new RegionServerCoprocessorRpcChannel(connection, sn);
   }
 
+  @Override
+  public void updateMasterConfiguration() throws IOException {
+    try {
+      this.connection.getMaster().updateMasterConfiguration(null,
+        UpdateMasterConfigurationRequest.getDefaultInstance());
+    } catch (ServiceException e) {
+      throw ProtobufUtil.getRemoteException(e);
+    }
+  }
+
   @Override
   public void updateConfiguration(ServerName server) throws IOException {
     try {

hbase-protocol/src/main/protobuf/Master.proto

@@ -382,6 +382,12 @@ message SetQuotaRequest {
 message SetQuotaResponse {
 }
 
+message UpdateMasterConfigurationRequest {
+}
+
+message UpdateMasterConfigurationResponse {
+}
+
 service MasterService {
   /** Used by the client to get the number of regions that have received the updated schema */
   rpc GetSchemaAlterStatus(GetSchemaAlterStatusRequest)
@@ -596,4 +602,7 @@ service MasterService {
 
   /** Apply the new quota settings */
   rpc SetQuota(SetQuotaRequest) returns(SetQuotaResponse);
+
+  rpc UpdateMasterConfiguration(UpdateMasterConfigurationRequest)
+    returns(UpdateMasterConfigurationResponse);
 }

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

@@ -1955,4 +1955,16 @@ public class HMaster extends HRegionServer implements MasterServices, Server {
     }
     return tableNames;
   }
+
+  /**
+   * Reload the configuration from disk.
+   */
+  public void updateConfiguration() {
+    LOG.info("Reloading the configuration from disk.");
+    // Reload the configuration from disk.
+    conf.reloadConfiguration();
+    synchronized (this.balancer) {
+      balancer.setConf(conf);
+    }
+  }
 }

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

@@ -144,6 +144,7 @@ import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.TruncateTableRequ
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.TruncateTableResponse;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UnassignRegionRequest;
 import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UnassignRegionResponse;
+import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UpdateMasterConfigurationResponse;
 import org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos.GetLastFlushedSequenceIdRequest;
 import org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos.GetLastFlushedSequenceIdResponse;
 import org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos.RegionServerReportRequest;
@@ -264,6 +265,14 @@ public class MasterRpcServices extends RSRpcServices
     bssi.addAll(super.getServices());
     return bssi;
   }
+  
+  @Override
+  public UpdateMasterConfigurationResponse updateMasterConfiguration(RpcController controller,
+      org.apache.hadoop.hbase.protobuf.generated.MasterProtos.UpdateMasterConfigurationRequest
+      request) throws ServiceException {
+    master.updateConfiguration();
+    return UpdateMasterConfigurationResponse.getDefaultInstance();
+  }
 
   @Override
   public GetLastFlushedSequenceIdResponse getLastFlushedSequenceId(RpcController controller,

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

@@ -135,15 +135,19 @@ public class StochasticLoadBalancer extends BaseLoadBalancer {
 
     numRegionLoadsToRemember = conf.getInt(KEEP_REGION_LOADS, numRegionLoadsToRemember);
 
-    localityCandidateGenerator = new LocalityBasedCandidateGenerator(services);
+    if (localityCandidateGenerator == null) {
+      localityCandidateGenerator = new LocalityBasedCandidateGenerator(services);
+    }
     localityCost = new LocalityCostFunction(conf, services);
 
-    candidateGenerators = new CandidateGenerator[] {
+    if (candidateGenerators == null) {
-      new RandomCandidateGenerator(),
+      candidateGenerators = new CandidateGenerator[] {
-      new LoadCandidateGenerator(),
+          new RandomCandidateGenerator(),
-      localityCandidateGenerator,
+          new LoadCandidateGenerator(),
-      new RegionReplicaRackCandidateGenerator(),
+          localityCandidateGenerator,
-    };
+          new RegionReplicaRackCandidateGenerator(),
+      };
+    }
 
     regionLoadFunctions = new CostFromRegionLoadFunction[] {
       new ReadRequestCostFunction(conf),

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestUpdateConfiguration.java

@@ -18,10 +18,17 @@
  */
 package org.apache.hadoop.hbase.client;
 
+import static org.junit.Assert.assertEquals;
+
 import java.io.IOException;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.testclassification.MediumTests;
@@ -46,4 +53,24 @@ public class TestUpdateConfiguration {
     ServerName server = TEST_UTIL.getHBaseCluster().getRegionServer(0).getServerName();
     admin.updateConfiguration(server);
   }
+
+  @Test
+  public void testMasterOnlineConfigChange() throws IOException {
+    LOG.debug("Starting the test");
+    Path cnfPath = FileSystems.getDefault().getPath("target/test-classes/hbase-site.xml");
+    Path cnf2Path = FileSystems.getDefault().getPath("target/test-classes/hbase-site2.xml");
+    Path cnf3Path = FileSystems.getDefault().getPath("target/test-classes/hbase-site3.xml");
+    // make a backup of hbase-site.xml
+    Files.copy(cnfPath, cnf3Path, StandardCopyOption.REPLACE_EXISTING);
+    // update hbase-site.xml by overwriting it
+    Files.copy(cnf2Path, cnfPath, StandardCopyOption.REPLACE_EXISTING);
+
+    Admin admin = TEST_UTIL.getHBaseAdmin();
+    admin.updateMasterConfiguration();
+    Configuration conf = TEST_UTIL.getMiniHBaseCluster().getMaster().getConfiguration();
+    int custom = conf.getInt("hbase.custom.config", 0);
+    assertEquals(custom, 1000);
+    // restore hbase-site.xml
+    Files.copy(cnf3Path, cnfPath, StandardCopyOption.REPLACE_EXISTING);
+  }
 }

hbase-server/src/test/resources/hbase-site2.xml

@@ -0,0 +1,154 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
+<!--
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+-->
+<configuration>
+  <property>
+    <name>hbase.custom.config</name>
+    <value>1000</value>
+  </property>
+  <property>
+    <name>hbase.regionserver.msginterval</name>
+    <value>1000</value>
+    <description>Interval between messages from the RegionServer to HMaster
+    in milliseconds.  Default is 15. Set this value low if you want unit
+    tests to be responsive.
+    </description>
+  </property>
+  <property>
+    <name>hbase.defaults.for.version.skip</name>
+    <value>true</value>
+  </property>
+  <property>
+    <name>hbase.server.thread.wakefrequency</name>
+    <value>1000</value>
+    <description>Time to sleep in between searches for work (in milliseconds).
+    Used as sleep interval by service threads such as hbase:meta scanner and log roller.
+    </description>
+  </property>
+  <property>
+    <name>hbase.master.event.waiting.time</name>
+    <value>50</value>
+    <description>Time to sleep between checks to see if a table event took place.
+    </description>
+  </property>
+  <property>
+    <name>hbase.regionserver.handler.count</name>
+    <value>5</value>
+  </property>
+  <property>
+    <name>hbase.master.info.port</name>
+    <value>-1</value>
+    <description>The port for the hbase master web UI
+    Set to -1 if you do not want the info server to run.
+    </description>
+  </property>
+  <property>
+    <name>hbase.master.port</name>
+    <value>0</value>
+    <description>Always have masters and regionservers come up on port '0' so we don't clash over
+      default ports.
+    </description>
+  </property>
+  <property>
+    <name>hbase.regionserver.port</name>
+    <value>0</value>
+    <description>Always have masters and regionservers come up on port '0' so we don't clash over
+      default ports.
+    </description>
+  </property>
+  <property>
+    <name>hbase.ipc.client.fallback-to-simple-auth-allowed</name>
+    <value>true</value>
+  </property>
+
+  <property>
+    <name>hbase.regionserver.info.port</name>
+    <value>-1</value>
+    <description>The port for the hbase regionserver web UI
+    Set to -1 if you do not want the info server to run.
+    </description>
+  </property>
+  <property>
+    <name>hbase.regionserver.info.port.auto</name>
+    <value>true</value>
+    <description>Info server auto port bind. Enables automatic port
+    search if hbase.regionserver.info.port is already in use.
+    Enabled for testing to run multiple tests on one machine.
+    </description>
+  </property>
+  <property>
+    <name>hbase.master.lease.thread.wakefrequency</name>
+    <value>3000</value>
+    <description>The interval between checks for expired region server leases.
+    This value has been reduced due to the other reduced values above so that
+    the master will notice a dead region server sooner. The default is 15 seconds.
+    </description>
+  </property>
+  <property>
+    <name>hbase.regionserver.safemode</name>
+    <value>false</value>
+    <description>
+    Turn on/off safe mode in region server. Always on for production, always off
+    for tests.
+    </description>
+  </property>
+  <property>
+    <name>hbase.hregion.max.filesize</name>
+    <value>67108864</value>
+    <description>
+    Maximum desired file size for an HRegion.  If filesize exceeds
+    value + (value / 2), the HRegion is split in two.  Default: 256M.
+
+    Keep the maximum filesize small so we split more often in tests.
+    </description>
+  </property>
+  <property>
+    <name>hadoop.log.dir</name>
+    <value>${user.dir}/../logs</value>
+  </property>
+  <property>
+    <name>hbase.zookeeper.property.clientPort</name>
+    <value>21818</value>
+    <description>Property from ZooKeeper's config zoo.cfg.
+    The port at which the clients will connect.
+    </description>
+  </property>
+  <property>
+    <name>hbase.defaults.for.version.skip</name>
+    <value>true</value>
+    <description>
+    Set to true to skip the 'hbase.defaults.for.version'.
+    Setting this to true can be useful in contexts other than
+    the other side of a maven generation; i.e. running in an
+    ide.  You'll want to set this boolean to true to avoid
+    seeing the RuntimException complaint: "hbase-default.xml file
+    seems to be for and old version of HBase (@@@VERSION@@@), this
+    version is X.X.X-SNAPSHOT"
+    </description>
+  </property>
+  <property>
+    <name>hbase.table.sanity.checks</name>
+    <value>false</value>
+    <description>Skip sanity checks in tests
+    </description>
+  </property>
+</configuration>