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 java.io.IOException; 23 24 import org.apache.hadoop.hbase.ClusterStatus; 25 import org.apache.hadoop.hbase.HColumnDescriptor; 26 import org.apache.hadoop.hbase.HTableDescriptor; 27 import org.apache.hadoop.hbase.UnknownRegionException; 28 29 /** 30 * Clients interact with the HMasterInterface to gain access to meta-level 31 * HBase functionality, like finding an HRegionServer and creating/destroying 32 * tables. 33 * 34 * <p>NOTE: if you change the interface, you must change the RPC version 35 * number in HBaseRPCProtocolVersion 36 * 37 */ 38 public interface HMasterInterface extends HBaseRPCProtocolVersion { 39 40 /** @return true if master is available */ 41 public boolean isMasterRunning(); 42 43 // Admin tools would use these cmds 44 45 /** 46 * Creates a new table. If splitKeys are specified, then the table will be 47 * created with an initial set of multiple regions. If splitKeys is null, 48 * the table will be created with a single region. 49 * @param desc table descriptor 50 * @param splitKeys 51 * @throws IOException 52 */ 53 public void createTable(HTableDescriptor desc, byte [][] splitKeys) 54 throws IOException; 55 56 /** 57 * Deletes a table 58 * @param tableName table to delete 59 * @throws IOException e 60 */ 61 public void deleteTable(final byte [] tableName) throws IOException; 62 63 /** 64 * Adds a column to the specified table 65 * @param tableName table to modify 66 * @param column column descriptor 67 * @throws IOException e 68 */ 69 public void addColumn(final byte [] tableName, HColumnDescriptor column) 70 throws IOException; 71 72 /** 73 * Modifies an existing column on the specified table 74 * @param tableName table name 75 * @param descriptor new column descriptor 76 * @throws IOException e 77 */ 78 public void modifyColumn(final byte [] tableName, HColumnDescriptor descriptor) 79 throws IOException; 80 81 82 /** 83 * Deletes a column from the specified table. Table must be disabled. 84 * @param tableName table to alter 85 * @param columnName column family to remove 86 * @throws IOException e 87 */ 88 public void deleteColumn(final byte [] tableName, final byte [] columnName) 89 throws IOException; 90 91 /** 92 * Puts the table on-line (only needed if table has been previously taken offline) 93 * @param tableName table to enable 94 * @throws IOException e 95 */ 96 public void enableTable(final byte [] tableName) throws IOException; 97 98 /** 99 * Take table offline 100 * 101 * @param tableName table to take offline 102 * @throws IOException e 103 */ 104 public void disableTable(final byte [] tableName) throws IOException; 105 106 /** 107 * Modify a table's metadata 108 * 109 * @param tableName table to modify 110 * @param htd new descriptor for table 111 * @throws IOException e 112 */ 113 public void modifyTable(byte[] tableName, HTableDescriptor htd) 114 throws IOException; 115 116 /** 117 * Shutdown an HBase cluster. 118 * @throws IOException e 119 */ 120 public void shutdown() throws IOException; 121 122 /** 123 * Stop HBase Master only. 124 * Does not shutdown the cluster. 125 * @throws IOException e 126 */ 127 public void stopMaster() throws IOException; 128 129 /** 130 * Return cluster status. 131 * @return status object 132 */ 133 public ClusterStatus getClusterStatus(); 134 135 136 /** 137 * Move the region <code>r</code> to <code>dest</code>. 138 * @param encodedRegionName The encoded region name; i.e. the hash that makes 139 * up the region name suffix: e.g. if regionname is 140 * <code>TestTable,0094429456,1289497600452.527db22f95c8a9e0116f0cc13c680396.</code>, 141 * then the encoded region name is: <code>527db22f95c8a9e0116f0cc13c680396</code>. 142 * @param destServerName The servername of the destination regionserver. If 143 * passed the empty byte array we'll assign to a random server. A server name 144 * is made of host, port and startcode. Here is an example: 145 * <code> host187.example.com,60020,1289493121758</code>. 146 * @throws UnknownRegionException Thrown if we can't find a region named 147 * <code>encodedRegionName</code> 148 */ 149 public void move(final byte [] encodedRegionName, final byte [] destServerName) 150 throws UnknownRegionException; 151 152 /** 153 * Assign a region to a server chosen at random. 154 * @param regionName Region to assign. Will use existing RegionPlan if one 155 * found. 156 * @param force If true, will force the assignment. 157 * @throws IOException 158 */ 159 public void assign(final byte [] regionName, final boolean force) 160 throws IOException; 161 162 /** 163 * Unassign a region from current hosting regionserver. Region will then be 164 * assigned to a regionserver chosen at random. Region could be reassigned 165 * back to the same server. Use {@link #move(byte[], byte[])} if you want 166 * to control the region movement. 167 * @param regionName Region to unassign. Will clear any existing RegionPlan 168 * if one found. 169 * @param force If true, force unassign (Will remove region from 170 * regions-in-transition too if present). 171 * @throws IOException 172 */ 173 public void unassign(final byte [] regionName, final boolean force) 174 throws IOException; 175 176 /** 177 * Run the balancer. Will run the balancer and if regions to move, it will 178 * go ahead and do the reassignments. Can NOT run for various reasons. Check 179 * logs. 180 * @return True if balancer ran and was able to tell the region servers to 181 * unassign all the regions to balance (the re-assignment itself is async), 182 * false otherwise. 183 */ 184 public boolean balance(); 185 186 /** 187 * Turn the load balancer on or off. 188 * @param b If true, enable balancer. If false, disable balancer. 189 * @return Previous balancer value 190 */ 191 public boolean balanceSwitch(final boolean b); 192 }