Hbase0.96源代码之HMaster(一)

从main（）函数开始

  public static void main(String [] args) {    VersionInfo.logVersion();    new HMasterCommandLine(HMaster.class).doMain(args);  }    public void doMain(String args[]) {    try {      int ret = ToolRunner.run(HBaseConfiguration.create(), this, args);      if (ret != 0) {        System.exit(ret);      }    } catch (Exception e) {      LOG.error("Failed to run", e);      System.exit(-1);    }  }

这里是使用的hadoop的ToolRunner，

public static int More ...run(Configuration conf, Tool tool, String[] args)     throws Exception{    if(conf == null) {      conf = new Configuration();    }    GenericOptionsParser parser = new GenericOptionsParser(conf, args);    //set the configuration back, so that Tool can configure itself    tool.setConf(conf);    //get the args w/o generic hadoop args    String[] toolArgs = parser.getRemainingArgs();    return tool.run(toolArgs);  }

其实就是走了一遍GenericOptionsParser解析参数，又回到tool.run(toolArgs);而这里的tool其实有这样的继承关系HMasterCommandLine-->ServerCommandLine-->Tool,而这里的tool其实有这样的继承关系HMasterCommandLine的run（）方法

  public int run(String args[]) throws Exception {    Options opt = new Options();    opt.addOption("localRegionServers", true,      "RegionServers to start in master process when running standalone");    opt.addOption("masters", true, "Masters to start in this process");    opt.addOption("minRegionServers", true, "Minimum RegionServers needed to host user tables");    opt.addOption("backup", false, "Do not try to become HMaster until the primary fails");    CommandLine cmd;    try {      cmd = new GnuParser().parse(opt, args);    } catch (ParseException e) {      LOG.error("Could not parse: ", e);      usage(null);      return 1;    }    if (cmd.hasOption("minRegionServers")) {      String val = cmd.getOptionValue("minRegionServers");      getConf().setInt("hbase.regions.server.count.min",                  Integer.valueOf(val));      LOG.debug("minRegionServers set to " + val);    }    // minRegionServers used to be minServers.  Support it too.    if (cmd.hasOption("minServers")) {      String val = cmd.getOptionValue("minServers");      getConf().setInt("hbase.regions.server.count.min",                  Integer.valueOf(val));      LOG.debug("minServers set to " + val);    }    // check if we are the backup master - override the conf if so    if (cmd.hasOption("backup")) {      getConf().setBoolean(HConstants.MASTER_TYPE_BACKUP, true);    }    // How many regionservers to startup in this process (we run regionservers in same process as    // master when we are in local/standalone mode. Useful testing)    if (cmd.hasOption("localRegionServers")) {      String val = cmd.getOptionValue("localRegionServers");      getConf().setInt("hbase.regionservers", Integer.valueOf(val));      LOG.debug("localRegionServers set to " + val);    }    // How many masters to startup inside this process; useful testing    if (cmd.hasOption("masters")) {      String val = cmd.getOptionValue("masters");      getConf().setInt("hbase.masters", Integer.valueOf(val));      LOG.debug("masters set to " + val);    }    List<String> remainingArgs = cmd.getArgList();    if (remainingArgs.size() != 1) {      usage(null);      return 1;    }    String command = remainingArgs.get(0);    if ("start".equals(command)) {      return startMaster();    } else if ("stop".equals(command)) {      return stopMaster();    } else if ("clear".equals(command)) {      return (ZNodeClearer.clear(getConf()) ? 0 : 1);    } else {      usage("Invalid command: " + command);      return 1;    }  }

启动的时候command="start",走startMaster（）

private int startMaster() {    Configuration conf = getConf();    try {      // If 'local', defer to LocalHBaseCluster instance.  Starts master      // and regionserver both in the one JVM.      if (LocalHBaseCluster.isLocal(conf)) {        final MiniZooKeeperCluster zooKeeperCluster = new MiniZooKeeperCluster(conf);        File zkDataPath = new File(conf.get(HConstants.ZOOKEEPER_DATA_DIR));        int zkClientPort = conf.getInt(HConstants.ZOOKEEPER_CLIENT_PORT, 0);        if (zkClientPort == 0) {          throw new IOException("No config value for "              + HConstants.ZOOKEEPER_CLIENT_PORT);        }        zooKeeperCluster.setDefaultClientPort(zkClientPort);        // login the zookeeper server principal (if using security)        ZKUtil.loginServer(conf, "hbase.zookeeper.server.keytab.file",          "hbase.zookeeper.server.kerberos.principal", null);        int clientPort = zooKeeperCluster.startup(zkDataPath);        if (clientPort != zkClientPort) {          String errorMsg = "Could not start ZK at requested port of " +            zkClientPort + ".  ZK was started at port: " + clientPort +            ".  Aborting as clients (e.g. shell) will not be able to find " +            "this ZK quorum.";          System.err.println(errorMsg);          throw new IOException(errorMsg);        }        conf.set(HConstants.ZOOKEEPER_CLIENT_PORT,                 Integer.toString(clientPort));        // Need to have the zk cluster shutdown when master is shutdown.        // Run a subclass that does the zk cluster shutdown on its way out.        LocalHBaseCluster cluster = new LocalHBaseCluster(conf, conf.getInt("hbase.masters", 1),          conf.getInt("hbase.regionservers", 1), LocalHMaster.class, HRegionServer.class);        ((LocalHMaster)cluster.getMaster(0)).setZKCluster(zooKeeperCluster);        cluster.startup();        waitOnMasterThreads(cluster);      } else {        logProcessInfo(getConf());        HMaster master = HMaster.constructMaster(masterClass, conf);        if (master.isStopped()) {          LOG.info("Won't bring the Master up as a shutdown is requested");          return 1;        }        master.start();        master.join();        if(master.isAborted())          throw new RuntimeException("HMaster Aborted");      }    } catch (Throwable t) {      LOG.error("Master exiting", t);      return 1;    }    return 0;  }

如果LocalHBaseCluster.isLocal（），启动一个本地集群LocalHBaseCluster，这里会在同一个JVM启动HMaster,HRegionServer
这里默认：hbase.cluster.distributed=false

  /** Cluster is in distributed mode or not */  public static final String CLUSTER_DISTRIBUTED = "hbase.cluster.distributed";  /** Config for pluggable load balancers */  public static final String HBASE_MASTER_LOADBALANCER_CLASS = "hbase.master.loadbalancer.class";  /** Cluster is standalone or pseudo-distributed */  public static final boolean CLUSTER_IS_LOCAL = false;  public static boolean isLocal(final Configuration c) {    boolean mode = c.getBoolean(HConstants.CLUSTER_DISTRIBUTED, HConstants.DEFAULT_CLUSTER_DISTRIBUTED);    return(mode == HConstants.CLUSTER_IS_LOCAL);  }

如果hbase.cluster.distributed=true,创建一个HMaster实例

logProcessInfo(getConf());HMaster master = HMaster.constructMaster(masterClass, conf);if (master.isStopped()) {  LOG.info("Won't bring the Master up as a shutdown is requested");  return 1;}master.start();master.join();if(master.isAborted())  throw new RuntimeException("HMaster Aborted");

构造HMaster

 Constructor<? extends HMaster> c =        masterClass.getConstructor(Configuration.class);      return c.newInstance(conf);

正是的构造函数：
1，获取master的地址，ip:port

public static final String MASTER_PORT = "hbase.master.port";为端口，默认60000int port = conf.getInt(HConstants.MASTER_PORT, HConstants.DEFAULT_MASTER_PORT);

2，处理RPC的handler的数量，由hbase.regionserver.handler.count
3，创建HMaster的RPCServer实例.
4，启动RPCServer的线程,
5, 创建zookeeper，创建hbase相关节点

  public HMaster(final Configuration conf)  throws IOException, KeeperException, InterruptedException {    this.conf = new Configuration(conf);    // Disable the block cache on the master    this.conf.setFloat(HConstants.HFILE_BLOCK_CACHE_SIZE_KEY, 0.0f);    // Server to handle client requests.    String hostname = Strings.domainNamePointerToHostName(DNS.getDefaultHost(      conf.get("hbase.master.dns.interface", "default"),      conf.get("hbase.master.dns.nameserver", "default")));    int port = conf.getInt(HConstants.MASTER_PORT, HConstants.DEFAULT_MASTER_PORT);    // Test that the hostname is reachable    InetSocketAddress initialIsa = new InetSocketAddress(hostname, port);    if (initialIsa.getAddress() == null) {      throw new IllegalArgumentException("Failed resolve of hostname " + initialIsa);    }    // Verify that the bind address is reachable if set    String bindAddress = conf.get("hbase.master.ipc.address");    if (bindAddress != null) {      initialIsa = new InetSocketAddress(bindAddress, port);      if (initialIsa.getAddress() == null) {        throw new IllegalArgumentException("Failed resolve of bind address " + initialIsa);      }    }    String name = "master/" + initialIsa.toString();    // Set how many times to retry talking to another server over HConnection.    HConnectionManager.setServerSideHConnectionRetries(this.conf, name, LOG);    int numHandlers = conf.getInt("hbase.master.handler.count",      conf.getInt("hbase.regionserver.handler.count", 25));    this.rpcServer = new RpcServer(this, name, getServices(),      initialIsa, // BindAddress is IP we got for this server.      numHandlers,      0, // we dont use high priority handlers in master      conf,      0); // this is a DNC w/o high priority handlers    // Set our address.    this.isa = this.rpcServer.getListenerAddress();    // We don't want to pass isa's hostname here since it could be 0.0.0.0    this.serverName = new ServerName(hostname, this.isa.getPort(), System.currentTimeMillis());    this.rsFatals = new MemoryBoundedLogMessageBuffer(      conf.getLong("hbase.master.buffer.for.rs.fatals", 1*1024*1024));    // login the zookeeper client principal (if using security)    ZKUtil.loginClient(this.conf, "hbase.zookeeper.client.keytab.file",      "hbase.zookeeper.client.kerberos.principal", this.isa.getHostName());    // initialize server principal (if using secure Hadoop)    User.login(conf, "hbase.master.keytab.file",      "hbase.master.kerberos.principal", this.isa.getHostName());    LOG.info("hbase.rootdir=" + FSUtils.getRootDir(this.conf) +        ", hbase.cluster.distributed=" + this.conf.getBoolean("hbase.cluster.distributed", false));    // set the thread name now we have an address    setName(MASTER + ":" + this.serverName.toShortString());    Replication.decorateMasterConfiguration(this.conf);    // Hack! Maps DFSClient => Master for logs.  HDFS made this    // config param for task trackers, but we can piggyback off of it.    if (this.conf.get("mapred.task.id") == null) {      this.conf.set("mapred.task.id", "hb_m_" + this.serverName.toString());    }    this.zooKeeper = new ZooKeeperWatcher(conf, MASTER + ":" + isa.getPort(), this, true);    this.rpcServer.startThreads();    this.pauseMonitor = new JvmPauseMonitor(conf);    this.pauseMonitor.start();    // metrics interval: using the same property as region server.    this.msgInterval = conf.getInt("hbase.regionserver.msginterval", 3 * 1000);    //should we check the compression codec type at master side, default true, HBASE-6370    this.masterCheckCompression = conf.getBoolean("hbase.master.check.compression", true);    this.metricsMaster = new MetricsMaster( new MetricsMasterWrapperImpl(this));    // Health checker thread.    int sleepTime = this.conf.getInt(HConstants.HEALTH_CHORE_WAKE_FREQ,      HConstants.DEFAULT_THREAD_WAKE_FREQUENCY);    if (isHealthCheckerConfigured()) {      healthCheckChore = new HealthCheckChore(sleepTime, this, getConfiguration());    }    // Do we publish the status?    boolean shouldPublish = conf.getBoolean(HConstants.STATUS_PUBLISHED,        HConstants.STATUS_PUBLISHED_DEFAULT);    Class<? extends ClusterStatusPublisher.Publisher> publisherClass =        conf.getClass(ClusterStatusPublisher.STATUS_PUBLISHER_CLASS,            ClusterStatusPublisher.DEFAULT_STATUS_PUBLISHER_CLASS,            ClusterStatusPublisher.Publisher.class);    if (shouldPublish) {      if (publisherClass == null) {        LOG.warn(HConstants.STATUS_PUBLISHED + " is true, but " +            ClusterStatusPublisher.DEFAULT_STATUS_PUBLISHER_CLASS +            " is not set - not publishing status");      } else {        clusterStatusPublisherChore = new ClusterStatusPublisher(this, conf, publisherClass);        Threads.setDaemonThreadRunning(clusterStatusPublisherChore.getThread());      }    }    distributedLogReplay = this.conf.getBoolean(HConstants.DISTRIBUTED_LOG_REPLAY_KEY,      HConstants.DEFAULT_DISTRIBUTED_LOG_REPLAY_CONFIG);  }

创建zookeeper，连接到zookeeper,创建hbase相关节点。
这里主要两个函数setNodeNames（）和createBaseZNodes（）

this.zooKeeper = new ZooKeeperWatcher(conf, MASTER + ":" + isa.getPort(), this, true);

  public ZooKeeperWatcher(Configuration conf, String identifier,      Abortable abortable, boolean canCreateBaseZNode)  throws IOException, ZooKeeperConnectionException {    this.conf = conf;    // Capture a stack trace now.  Will print it out later if problem so we can    // distingush amongst the myriad ZKWs.    try {      throw new Exception("ZKW CONSTRUCTOR STACK TRACE FOR DEBUGGING");    } catch (Exception e) {      this.constructorCaller = e;    }    this.quorum = ZKConfig.getZKQuorumServersString(conf);    // Identifier will get the sessionid appended later below down when we    // handle the syncconnect event.    this.identifier = identifier;    this.abortable = abortable;    setNodeNames(conf);    this.recoverableZooKeeper = ZKUtil.connect(conf, quorum, this, identifier);    if (canCreateBaseZNode) {      createBaseZNodes();    }  }

HMaster的主循环的run（）方法，这里主要关心
1，becomeActiveMaster(startupStatus);

2，finishInitialization(startupStatus, false);

3，loop()

  @Override  public void run() {    MonitoredTask startupStatus =      TaskMonitor.get().createStatus("Master startup");    startupStatus.setDescription("Master startup");    masterStartTime = System.currentTimeMillis();    try {      this.registeredZKListenersBeforeRecovery = this.zooKeeper.getListeners();      this.masterAddressManager = new MasterAddressTracker(getZooKeeperWatcher(), this);      this.masterAddressManager.start();      // Put up info server.      int port = this.conf.getInt("hbase.master.info.port", 60010);      if (port >= 0) {        String a = this.conf.get("hbase.master.info.bindAddress", "0.0.0.0");        this.infoServer = new InfoServer(MASTER, a, port, false, this.conf);        this.infoServer.addServlet("status", "/master-status", MasterStatusServlet.class);        this.infoServer.addServlet("dump", "/dump", MasterDumpServlet.class);        this.infoServer.setAttribute(MASTER, this);        this.infoServer.start();      }      /*       * Block on becoming the active master.       *       * We race with other masters to write our address into ZooKeeper.  If we       * succeed, we are the primary/active master and finish initialization.       *       * If we do not succeed, there is another active master and we should       * now wait until it dies to try and become the next active master.  If we       * do not succeed on our first attempt, this is no longer a cluster startup.       */      becomeActiveMaster(startupStatus);      // We are either the active master or we were asked to shutdown      if (!this.stopped) {        finishInitialization(startupStatus, false);        loop();      }    } catch (Throwable t) {      // HBASE-5680: Likely hadoop23 vs hadoop 20.x/1.x incompatibility      if (t instanceof NoClassDefFoundError &&          t.getMessage().contains("org/apache/hadoop/hdfs/protocol/FSConstants$SafeModeAction")) {          // improved error message for this special case          abort("HBase is having a problem with its Hadoop jars.  You may need to "              + "recompile HBase against Hadoop version "              +  org.apache.hadoop.util.VersionInfo.getVersion()              + " or change your hadoop jars to start properly", t);      } else {        abort("Unhandled exception. Starting shutdown.", t);      }    } finally {      startupStatus.cleanup();      stopChores();      // Wait for all the remaining region servers to report in IFF we were      // running a cluster shutdown AND we were NOT aborting.      if (!this.abort && this.serverManager != null &&          this.serverManager.isClusterShutdown()) {        this.serverManager.letRegionServersShutdown();      }      stopServiceThreads();      // Stop services started for both backup and active masters      if (this.activeMasterManager != null) this.activeMasterManager.stop();      if (this.catalogTracker != null) this.catalogTracker.stop();      if (this.serverManager != null) this.serverManager.stop();      if (this.assignmentManager != null) this.assignmentManager.stop();      if (this.fileSystemManager != null) this.fileSystemManager.stop();      if (this.snapshotManager != null) this.snapshotManager.stop("server shutting down.");      this.zooKeeper.close();    }    LOG.info("HMaster main thread exiting");  }