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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.hadoop.hbase.chaos.actions;
20  
21  import java.util.LinkedList;
22  import java.util.List;
23  import java.util.Queue;
24  
25  import org.apache.commons.lang.math.RandomUtils;
26  import org.apache.hadoop.hbase.ServerName;
27  import org.apache.hadoop.hbase.chaos.monkies.PolicyBasedChaosMonkey;
28  
29  /**
30   * Restarts a ratio of the regionservers in a rolling fashion. At each step, either kills a
31   * server, or starts one, sleeping randomly (0-sleepTime) in between steps.
32   */
33  public class RollingBatchRestartRsAction extends BatchRestartRsAction {
34    public RollingBatchRestartRsAction(long sleepTime, float ratio) {
35      super(sleepTime, ratio);
36    }
37  
38    @Override
39    public void perform() throws Exception {
40      LOG.info(String.format("Performing action: Rolling batch restarting %d%% of region servers",
41          (int)(ratio * 100)));
42      List<ServerName> selectedServers = PolicyBasedChaosMonkey.selectRandomItems(getCurrentServers(),
43          ratio);
44  
45      Queue<ServerName> serversToBeKilled = new LinkedList<ServerName>(selectedServers);
46      Queue<ServerName> deadServers = new LinkedList<ServerName>();
47  
48      //
49      while (!serversToBeKilled.isEmpty() || !deadServers.isEmpty()) {
50        boolean action = true; //action true = kill server, false = start server
51  
52        if (serversToBeKilled.isEmpty() || deadServers.isEmpty()) {
53          action = deadServers.isEmpty();
54        } else {
55          action = RandomUtils.nextBoolean();
56        }
57  
58        if (action) {
59          ServerName server = serversToBeKilled.remove();
60          killRs(server);
61          deadServers.add(server);
62        } else {
63          ServerName server = deadServers.remove();
64          startRs(server);
65        }
66  
67        sleep(RandomUtils.nextInt((int)sleepTime));
68      }
69    }
70  }