1   /**
2    * Copyright 2007 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  package org.apache.hadoop.hbase.master;
21  
22  import java.io.IOException;
23  import java.util.ArrayList;
24  import java.util.List;
25  
26  import org.apache.hadoop.hbase.HBaseConfiguration;
27  import org.apache.hadoop.hbase.HMsg;
28  import org.apache.hadoop.hbase.HRegionInfo;
29  import org.apache.hadoop.hbase.HServerInfo;
30  
31  /**
32   * An HMaster that runs out of memory.
33   * Everytime a region server reports in, add to the retained heap of memory.
34   * Needs to be started manually as in
35   * <code>${HBASE_HOME}/bin/hbase ./bin/hbase org.apache.hadoop.hbase.OOMEHMaster start/code>.
36   */
37  public class OOMEHMaster extends HMaster {
38    private List<byte []> retainer = new ArrayList<byte[]>();
39  
40    public OOMEHMaster(HBaseConfiguration conf) throws IOException {
41      super(conf);
42    }
43  
44    @Override
45    public HMsg[] regionServerReport(HServerInfo serverInfo, HMsg[] msgs,
46      HRegionInfo[] mostLoadedRegions)
47    throws IOException {
48      // Retain 1M.
49      this.retainer.add(new byte [1024 * 1024]);
50      return super.regionServerReport(serverInfo, msgs, mostLoadedRegions);
51    }
52  
53    /**
54     * @param args
55     */
56    public static void main(String[] args) {
57      doMain(args, OOMEHMaster.class);
58    }
59  }