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.ha;
019
020import java.io.IOException;
021import java.net.InetSocketAddress;
022import java.util.Map;
023
024import javax.net.SocketFactory;
025
026import org.apache.hadoop.classification.InterfaceAudience;
027import org.apache.hadoop.classification.InterfaceStability;
028import org.apache.hadoop.conf.Configuration;
029import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
030import org.apache.hadoop.ha.protocolPB.HAServiceProtocolClientSideTranslatorPB;
031import org.apache.hadoop.ha.protocolPB.ZKFCProtocolClientSideTranslatorPB;
032import org.apache.hadoop.net.NetUtils;
033
034import com.google.common.collect.Maps;
035
036/**
037 * Represents a target of the client side HA administration commands.
038 */
039@InterfaceAudience.Public
040@InterfaceStability.Evolving
041public abstract class HAServiceTarget {
042
043  private static final String HOST_SUBST_KEY = "host";
044  private static final String PORT_SUBST_KEY = "port";
045  private static final String ADDRESS_SUBST_KEY = "address";
046
047  /**
048   * @return the IPC address of the target node.
049   */
050  public abstract InetSocketAddress getAddress();
051
052  /**
053   * @return the IPC address of the ZKFC on the target node
054   */
055  public abstract InetSocketAddress getZKFCAddress();
056
057  /**
058   * @return a Fencer implementation configured for this target node
059   */
060  public abstract NodeFencer getFencer();
061  
062  /**
063   * @throws BadFencingConfigurationException if the fencing configuration
064   * appears to be invalid. This is divorced from the above
065   * {@link #getFencer()} method so that the configuration can be checked
066   * during the pre-flight phase of failover.
067   */
068  public abstract void checkFencingConfigured()
069      throws BadFencingConfigurationException;
070  
071  /**
072   * @return a proxy to connect to the target HA Service.
073   */
074  public HAServiceProtocol getProxy(Configuration conf, int timeoutMs)
075      throws IOException {
076    Configuration confCopy = new Configuration(conf);
077    // Lower the timeout so we quickly fail to connect
078    confCopy.setInt(CommonConfigurationKeysPublic.IPC_CLIENT_CONNECT_MAX_RETRIES_KEY, 1);
079    SocketFactory factory = NetUtils.getDefaultSocketFactory(confCopy);
080    return new HAServiceProtocolClientSideTranslatorPB(
081        getAddress(),
082        confCopy, factory, timeoutMs);
083  }
084  
085  /**
086   * @return a proxy to the ZKFC which is associated with this HA service.
087   */
088  public ZKFCProtocol getZKFCProxy(Configuration conf, int timeoutMs)
089      throws IOException {
090    Configuration confCopy = new Configuration(conf);
091    // Lower the timeout so we quickly fail to connect
092    confCopy.setInt(CommonConfigurationKeysPublic.IPC_CLIENT_CONNECT_MAX_RETRIES_KEY, 1);
093    SocketFactory factory = NetUtils.getDefaultSocketFactory(confCopy);
094    return new ZKFCProtocolClientSideTranslatorPB(
095        getZKFCAddress(),
096        confCopy, factory, timeoutMs);
097  }
098  
099  public final Map<String, String> getFencingParameters() {
100    Map<String, String> ret = Maps.newHashMap();
101    addFencingParameters(ret);
102    return ret;
103  }
104  
105  /**
106   * Hook to allow subclasses to add any parameters they would like to
107   * expose to fencing implementations/scripts. Fencing methods are free
108   * to use this map as they see fit -- notably, the shell script
109   * implementation takes each entry, prepends 'target_', substitutes
110   * '_' for '.', and adds it to the environment of the script.
111   *
112   * Subclass implementations should be sure to delegate to the superclass
113   * implementation as well as adding their own keys.
114   *
115   * @param ret map which can be mutated to pass parameters to the fencer
116   */
117  protected void addFencingParameters(Map<String, String> ret) {
118    ret.put(ADDRESS_SUBST_KEY, String.valueOf(getAddress()));
119    ret.put(HOST_SUBST_KEY, getAddress().getHostName());
120    ret.put(PORT_SUBST_KEY, String.valueOf(getAddress().getPort()));
121  }
122
123  /**
124   * @return true if auto failover should be considered enabled
125   */
126  public boolean isAutoFailoverEnabled() {
127    return false;
128  }
129}