| /** |
| * 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. |
| */ |
| package org.apache.hadoop.hbase.master.balancer; |
| |
| import java.io.IOException; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.stream.Collectors; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.conf.Configured; |
| import org.apache.hadoop.hbase.ClusterMetrics; |
| import org.apache.hadoop.hbase.ServerName; |
| import org.apache.hadoop.hbase.TableName; |
| import org.apache.hadoop.hbase.client.RegionInfo; |
| import org.apache.hadoop.hbase.master.LoadBalancer; |
| import org.apache.hadoop.hbase.master.RegionPlan; |
| import org.apache.yetus.audience.InterfaceAudience; |
| |
| /** |
| * a balancer which is only used in maintenance mode. |
| */ |
| @InterfaceAudience.Private |
| public class MaintenanceLoadBalancer extends Configured implements LoadBalancer { |
| |
| private volatile boolean stopped = false; |
| |
| @Override |
| public void stop(String why) { |
| stopped = true; |
| } |
| |
| @Override |
| public boolean isStopped() { |
| return stopped; |
| } |
| |
| @Override |
| public void setClusterMetrics(ClusterMetrics st) { |
| } |
| |
| @Override |
| public void setClusterInfoProvider(ClusterInfoProvider provider) { |
| } |
| |
| @Override |
| public List<RegionPlan> balanceCluster( |
| Map<TableName, Map<ServerName, List<RegionInfo>>> loadOfAllTable) throws IOException { |
| // do not need to balance in maintenance mode |
| return Collections.emptyList(); |
| } |
| |
| private Map<ServerName, List<RegionInfo>> assign(Collection<RegionInfo> regions, |
| List<ServerName> servers) { |
| // should only have 1 region server in maintenance mode |
| assert servers.size() == 1; |
| List<RegionInfo> systemRegions = |
| regions.stream().filter(r -> r.getTable().isSystemTable()).collect(Collectors.toList()); |
| if (!systemRegions.isEmpty()) { |
| return Collections.singletonMap(servers.get(0), systemRegions); |
| } else { |
| return Collections.emptyMap(); |
| } |
| } |
| |
| @Override |
| public Map<ServerName, List<RegionInfo>> roundRobinAssignment(List<RegionInfo> regions, |
| List<ServerName> servers) throws IOException { |
| return assign(regions, servers); |
| } |
| |
| @Override |
| public Map<ServerName, List<RegionInfo>> retainAssignment(Map<RegionInfo, ServerName> regions, |
| List<ServerName> servers) throws IOException { |
| return assign(regions.keySet(), servers); |
| } |
| |
| @Override |
| public ServerName randomAssignment(RegionInfo regionInfo, List<ServerName> servers) |
| throws IOException { |
| // should only have 1 region server in maintenance mode |
| assert servers.size() == 1; |
| return regionInfo.getTable().isSystemTable() ? servers.get(0) : null; |
| } |
| |
| @Override |
| public void initialize() { |
| } |
| |
| @Override |
| public void regionOnline(RegionInfo regionInfo, ServerName sn) { |
| } |
| |
| @Override |
| public void regionOffline(RegionInfo regionInfo) { |
| } |
| |
| @Override |
| public void onConfigurationChange(Configuration conf) { |
| } |
| |
| @Override |
| public void postMasterStartupInitialize() { |
| } |
| |
| @Override |
| public void updateBalancerStatus(boolean status) { |
| } |
| |
| } |