View Javadoc

1   /**
2    * Copyright 2010 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.ipc;
21  
22  import org.apache.hadoop.hbase.HMsg;
23  import org.apache.hadoop.hbase.HRegionInfo;
24  import org.apache.hadoop.hbase.HServerInfo;
25  import org.apache.hadoop.io.MapWritable;
26  
27  import java.io.IOException;
28  
29  /**
30   * HRegionServers interact with the HMasterRegionInterface to report on local
31   * goings-on and to obtain data-handling instructions from the HMaster.
32   * <p>Changes here need to be reflected in HbaseObjectWritable HbaseRPC#Invoker.
33   *
34   * <p>NOTE: if you change the interface, you must change the RPC version
35   * number in HBaseRPCProtocolVersion
36   *
37   */
38  public interface HMasterRegionInterface extends HBaseRPCProtocolVersion {
39  
40    /**
41     * Called when a region server first starts
42     * @param info server info
43     * @param serverCurrentTime The current time of the region server in ms
44     * @throws IOException e
45     * @return Configuration for the regionserver to use: e.g. filesystem,
46     * hbase rootdir, etc.
47     */
48    public MapWritable regionServerStartup(HServerInfo info,
49      long serverCurrentTime) throws IOException;
50  
51    /**
52     * Called to renew lease, tell master what the region server is doing and to
53     * receive new instructions from the master
54     *
55     * @param info server's address and start code
56     * @param msgs things the region server wants to tell the master
57     * @param mostLoadedRegions Array of HRegionInfos that should contain the
58     * reporting server's most loaded regions. These are candidates for being
59     * rebalanced.
60     * @return instructions from the master to the region server
61     * @throws IOException e
62     */
63    public HMsg[] regionServerReport(HServerInfo info, HMsg msgs[],
64      HRegionInfo mostLoadedRegions[])
65    throws IOException;
66  }