001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.master;
019
020import java.io.IOException;
021import java.io.UncheckedIOException;
022import java.util.HashSet;
023import java.util.Set;
024import org.apache.hadoop.hbase.Abortable;
025import org.apache.hadoop.hbase.HConstants;
026import org.apache.hadoop.hbase.ServerName;
027import org.apache.hadoop.hbase.client.Delete;
028import org.apache.hadoop.hbase.client.Put;
029import org.apache.hadoop.hbase.client.Result;
030import org.apache.hadoop.hbase.client.ResultScanner;
031import org.apache.hadoop.hbase.client.Scan;
032import org.apache.hadoop.hbase.log.HBaseMarkers;
033import org.apache.hadoop.hbase.master.assignment.ServerState;
034import org.apache.hadoop.hbase.master.region.MasterRegion;
035import org.apache.hadoop.hbase.master.region.MasterRegionFactory;
036import org.apache.hadoop.hbase.util.Bytes;
037import org.apache.yetus.audience.InterfaceAudience;
038import org.slf4j.Logger;
039import org.slf4j.LoggerFactory;
040
041/**
042 * {@link MasterRegion} based {@link RegionServerList}.
043 * <p/>
044 * This is useful when we want to restart a cluster with only the data on file system, as when
045 * restarting, we need to get the previous live region servers for scheduling SCP. Before we have
046 * this class, we need to scan the WAL directory on WAL file system to find out the previous live
047 * region servers, which means we can not restart a cluster without the previous WAL file system,
048 * even if we have flushed all the data.
049 * <p/>
050 * Please see HBASE-26245 for more details.
051 */
052@InterfaceAudience.Private
053public class MasterRegionServerList implements RegionServerList {
054
055  private static final Logger LOG = LoggerFactory.getLogger(MasterRegionServerList.class);
056
057  private final MasterRegion region;
058
059  private final Abortable abortable;
060
061  public MasterRegionServerList(MasterRegion region, Abortable abortable) {
062    this.region = region;
063    this.abortable = abortable;
064  }
065
066  @Override
067  public void started(ServerName sn) {
068    Put put =
069      new Put(Bytes.toBytes(sn.getServerName())).addColumn(MasterRegionFactory.REGION_SERVER_FAMILY,
070        HConstants.STATE_QUALIFIER, Bytes.toBytes(ServerState.ONLINE.name()));
071    try {
072      region.update(r -> r.put(put));
073    } catch (IOException e) {
074      LOG.error(HBaseMarkers.FATAL, "Failed to record region server {} as started, aborting...", sn,
075        e);
076      abortable.abort("Failed to record region server as started");
077      throw new UncheckedIOException(e);
078    }
079  }
080
081  @Override
082  public void expired(ServerName sn) {
083    Delete delete = new Delete(Bytes.toBytes(sn.getServerName()))
084      .addFamily(MasterRegionFactory.REGION_SERVER_FAMILY);
085    try {
086      region.update(r -> r.delete(delete));
087    } catch (IOException e) {
088      LOG.error(HBaseMarkers.FATAL, "Failed to record region server {} as expired, aborting...", sn,
089        e);
090      abortable.abort("Failed to record region server as expired");
091      throw new UncheckedIOException(e);
092    }
093  }
094
095  @Override
096  public Set<ServerName> getAll() throws IOException {
097    Set<ServerName> rsList = new HashSet<>();
098    try (ResultScanner scanner =
099      region.getScanner(new Scan().addFamily(MasterRegionFactory.REGION_SERVER_FAMILY))) {
100      for (;;) {
101        Result result = scanner.next();
102        if (result == null) {
103          break;
104        }
105        rsList.add(ServerName.valueOf(Bytes.toString(result.getRow())));
106      }
107    }
108    return rsList;
109  }
110
111}