| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hbase.master; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.hbase.ServerName; |
| import org.apache.hadoop.hbase.util.ReflectionUtils; |
| import org.apache.hadoop.net.DNSToSwitchMapping; |
| import org.apache.hadoop.net.ScriptBasedMapping; |
| /** |
| * Wrapper over the rack resolution utility in Hadoop. The rack resolution |
| * utility in Hadoop does resolution from hosts to the racks they belong to. |
| * |
| */ |
| @InterfaceAudience.Private |
| public class RackManager { |
| private static final Log LOG = LogFactory.getLog(RackManager.class); |
| public static final String UNKNOWN_RACK = "Unknown Rack"; |
| |
| private DNSToSwitchMapping switchMapping; |
| |
| public RackManager() { |
| } |
| |
| public RackManager(Configuration conf) { |
| switchMapping = ReflectionUtils.instantiateWithCustomCtor( |
| conf.getClass("hbase.util.ip.to.rack.determiner", ScriptBasedMapping.class, |
| DNSToSwitchMapping.class).getName(), new Class<?>[]{Configuration.class}, |
| new Object[]{conf}); |
| } |
| |
| /** |
| * Get the name of the rack containing a server, according to the DNS to |
| * switch mapping. |
| * @param server the server for which to get the rack name |
| * @return the rack name of the server |
| */ |
| public String getRack(ServerName server) { |
| if (server == null) { |
| return UNKNOWN_RACK; |
| } |
| // just a note - switchMapping caches results (at least the implementation should unless the |
| // resolution is really a lightweight process) |
| List<String> racks = switchMapping.resolve(Arrays.asList(server.getHostname())); |
| if (racks != null && !racks.isEmpty()) { |
| return racks.get(0); |
| } |
| |
| return UNKNOWN_RACK; |
| } |
| |
| /** |
| * Same as {@link #getRack(ServerName)} except that a list is passed |
| * @param servers list of servers we're requesting racks information for |
| * @return list of racks for the given list of servers |
| */ |
| public List<String> getRack(List<ServerName> servers) { |
| // just a note - switchMapping caches results (at least the implementation should unless the |
| // resolution is really a lightweight process) |
| List<String> serversAsString = new ArrayList<String>(servers.size()); |
| for (ServerName server : servers) { |
| serversAsString.add(server.getHostname()); |
| } |
| List<String> racks = switchMapping.resolve(serversAsString); |
| return racks; |
| } |
| } |