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.balancer;
019
020import java.io.IOException;
021import java.util.Collection;
022import java.util.List;
023import java.util.Map;
024import java.util.function.Predicate;
025import java.util.function.Supplier;
026import org.apache.hadoop.conf.Configuration;
027import org.apache.hadoop.hbase.HDFSBlocksDistribution;
028import org.apache.hadoop.hbase.ServerMetrics;
029import org.apache.hadoop.hbase.ServerName;
030import org.apache.hadoop.hbase.TableName;
031import org.apache.hadoop.hbase.client.BalancerDecision;
032import org.apache.hadoop.hbase.client.BalancerRejection;
033import org.apache.hadoop.hbase.client.Connection;
034import org.apache.hadoop.hbase.client.RegionInfo;
035import org.apache.hadoop.hbase.client.TableDescriptor;
036import org.apache.hadoop.hbase.conf.ConfigurationObserver;
037import org.apache.yetus.audience.InterfaceAudience;
038
039/**
040 * This is the cluster we want to balance. It provides methods to let us get the information we
041 * want.
042 */
043@InterfaceAudience.Private
044public interface ClusterInfoProvider extends ConfigurationObserver {
045
046  /**
047   * Get the configuration.
048   */
049  Configuration getConfiguration();
050
051  /**
052   * Returns a reference to the cluster's connection.
053   */
054  Connection getConnection();
055
056  /**
057   * Get all the regions of this cluster.
058   * <p/>
059   * Used to refresh region block locations on HDFS.
060   */
061  List<RegionInfo> getAssignedRegions();
062
063  /**
064   * Unassign the given region.
065   */
066  void unassign(RegionInfo regionInfo) throws IOException;
067
068  /**
069   * Get the table descriptor for the given table.
070   */
071  TableDescriptor getTableDescriptor(TableName tableName) throws IOException;
072
073  /**
074   * Returns the number of tables on this cluster.
075   */
076  int getNumberOfTables() throws IOException;
077
078  /**
079   * Compute the block distribution for the given region.
080   * <p/>
081   * Used to refresh region block locations on HDFS.
082   */
083  HDFSBlocksDistribution computeHDFSBlocksDistribution(Configuration conf,
084    TableDescriptor tableDescriptor, RegionInfo regionInfo) throws IOException;
085
086  /**
087   * Check whether we have region replicas enabled for the tables of the given regions.
088   */
089  boolean hasRegionReplica(Collection<RegionInfo> regions) throws IOException;
090
091  /**
092   * Returns a copy of the internal list of online servers.
093   */
094  List<ServerName> getOnlineServersList();
095
096  /**
097   * Returns a copy of the internal list of online servers matched by the given {@code filter}.
098   */
099  List<ServerName> getOnlineServersListWithPredicator(List<ServerName> servers,
100    Predicate<ServerMetrics> filter);
101
102  /**
103   * Get a snapshot of the current assignment status.
104   */
105  Map<ServerName, List<RegionInfo>> getSnapShotOfAssignment(Collection<RegionInfo> regions);
106
107  /**
108   * Test whether we are in off peak hour.
109   * <p/>
110   * For peak and off peak hours we may have different cost for the same balancing operation.
111   */
112  boolean isOffPeakHour();
113
114  /**
115   * Record the given balancer decision.
116   */
117  void recordBalancerDecision(Supplier<BalancerDecision> decision);
118
119  /**
120   * Record the given balancer rejection.
121   */
122  void recordBalancerRejection(Supplier<BalancerRejection> rejection);
123
124  /**
125   * Returns server metrics of the given server if serverName is known else null
126   */
127  ServerMetrics getLoad(ServerName serverName);
128}