| /** |
| * 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.net; |
| |
| import org.apache.hadoop.conf.Configuration; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Implements the {@link DNSToSwitchMapping} via static mappings. Used |
| * in testcases that simulate racks, and in the |
| * {@link org.apache.hadoop.hdfs.MiniDFSCluster} |
| * |
| * A shared, static mapping is used; to reset it call {@link #resetMap()}. |
| * |
| * When an instance of the class has its {@link #setConf(Configuration)} |
| * method called, nodes listed in the configuration will be added to the map. |
| * These do not get removed when the instance is garbage collected. |
| * |
| * The switch mapping policy of this class is the same as for the |
| * {@link ScriptBasedMapping} -the presence of a non-empty topology script. |
| * The script itself is not used. |
| */ |
| public class StaticMapping extends AbstractDNSToSwitchMapping { |
| |
| /** |
| * Key to define the node mapping as a comma-delimited list of host=rack |
| * mappings, e.g. <code>host1=r1,host2=r1,host3=r2</code>. |
| * <p/> |
| * Value: {@value} |
| * <p/> |
| * <b>Important: </b>spaces not trimmed and are considered significant. |
| */ |
| public static final String KEY_HADOOP_CONFIGURED_NODE_MAPPING = |
| "hadoop.configured.node.mapping"; |
| |
| /** |
| * Configure the mapping by extracting any mappings defined in the |
| * {@link #KEY_HADOOP_CONFIGURED_NODE_MAPPING} field |
| * @param conf new configuration |
| */ |
| @Override |
| public void setConf(Configuration conf) { |
| super.setConf(conf); |
| if (conf != null) { |
| String[] mappings = conf.getStrings(KEY_HADOOP_CONFIGURED_NODE_MAPPING); |
| if (mappings != null) { |
| for (String str : mappings) { |
| String host = str.substring(0, str.indexOf('=')); |
| String rack = str.substring(str.indexOf('=') + 1); |
| addNodeToRack(host, rack); |
| } |
| } |
| } |
| } |
| |
| /** |
| * retained lower case setter for compatibility reasons; relays to |
| * {@link #setConf(Configuration)} |
| * @param conf new configuration |
| */ |
| public void setconf(Configuration conf) { |
| setConf(conf); |
| } |
| |
| /* Only one instance per JVM */ |
| private static final Map<String, String> nameToRackMap = new HashMap<String, String>(); |
| |
| /** |
| * Add a node to the static map. The moment any entry is added to the map, |
| * the map goes multi-rack. |
| * @param name node name |
| * @param rackId rack ID |
| */ |
| public static void addNodeToRack(String name, String rackId) { |
| synchronized (nameToRackMap) { |
| nameToRackMap.put(name, rackId); |
| } |
| } |
| |
| @Override |
| public List<String> resolve(List<String> names) { |
| List<String> m = new ArrayList<String>(); |
| synchronized (nameToRackMap) { |
| for (String name : names) { |
| String rackId; |
| if ((rackId = nameToRackMap.get(name)) != null) { |
| m.add(rackId); |
| } else { |
| m.add(NetworkTopology.DEFAULT_RACK); |
| } |
| } |
| return m; |
| } |
| } |
| |
| /** |
| * The switch policy of this mapping is driven by the same policy |
| * as the Scripted mapping: the presence of the script name in |
| * the configuration file |
| * @return false, always |
| */ |
| @Override |
| public boolean isSingleSwitch() { |
| return isSingleSwitchByScriptPolicy(); |
| } |
| |
| /** |
| * Get a copy of the map (for diagnostics) |
| * @return a clone of the map or null for none known |
| */ |
| @Override |
| public Map<String, String> getSwitchMap() { |
| synchronized (nameToRackMap) { |
| return new HashMap<String, String>(nameToRackMap); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return "static mapping with single switch = " + isSingleSwitch(); |
| } |
| |
| /** |
| * Clear the map |
| */ |
| public static void resetMap() { |
| synchronized (nameToRackMap) { |
| nameToRackMap.clear(); |
| } |
| } |
| |
| public void reloadCachedMappings() { |
| // reloadCachedMappings does nothing for StaticMapping; there is |
| // nowhere to reload from since all data is in memory. |
| } |
| |
| @Override |
| public void reloadCachedMappings(List<String> names) { |
| // reloadCachedMappings does nothing for StaticMapping; there is |
| // nowhere to reload from since all data is in memory. |
| } |
| } |