HBase--HMaster的启动流程

2019-04-08

HBase

HMaster加载配置
ZK启动
创建master线程
启动regionServer类似

　　本篇文章主要来看一看HMaster的启动流程，直接进入主题吧。
ps:这些文章都是从我先记录到我为知笔记然后有空了就写成博客的，mac的为知笔记图片保存不是很方便，这篇文章的图片通过截图过来的上传后发现有点模糊，只能将就看了。

HMaster加载配置

org.apache.hadoop.hbase.master.HMaster 调用类中的main方法
在main方法中主要做了

打印启动日志，
调用HMasterCommandLine对象doMain()方法
a). 日志打打印

b). 调用HMasterCommandLine对象doMain()方法
HMasterCommandLine extends ServerCommandLine而HMasterCommandLine没有重写doMain()方法，即调用了o.a.h.h.u.ServerCommandLine接口中的doMain()方法
hbase HMasterCommandLine
doMain()方法，采用了Hadoop的ToolRunner机制

c). 先来看看，org.apache.hadoop.hbase.HBaseConfiguration的create()方法，从字面意思就知道是在创建配置文件
hbase HBaseConfiguration的create

d). 加载：core-default.xml,core-site.xml,hbase-default.xml,hbase-sute.xml
hbase 加载配置

加载配置看完了之后，回退回来继续看
ToolRunner.run(HBaseConfiguration.create(), this, args);
即:
org.apache.hadoop.util.ToolRunner.run,
如下：
将conf和args封装成GenericOptionsParser对象parser, 根据parser获取toolArgs
返回tool.run(toolArgs);
tool.run(toolArgs)也即HMasterComandLine.run(toolArgs)
org.apache.hadoop.hbase.master.HMasterComandLine.run(toolArgs)，重点在下面的startMaster()私有方法
重点来看看：org.apache.hadoop.hbase.master.HMasterCommandLine.startMaster()
由于代码过长我就不截图了
从注释就知道会有两种模式：本地模式和分布式模式。
1）本地模式local，master,regionserver,ZK都在同一个JVM中;
2）分布式模式distributed，仅只会启动一个HMaster对象。
代码里面大部分就是做一些配置处理，zk地址端口等，重点关注

local本地模式：ZK启动MiniZooKeeperCluster.startup(zkDataPath);
local本地模式：hmser,regionserver启动LocalHBaseCluster.startup();

distributed分布式模式：HMaster启动，HMaster.start()。

private int startMaster() {
    Configuration conf = getConf();
    TraceUtil.initTracer(conf);

    try {
      // If 'local', defer to LocalHBaseCluster instance.  Starts master
      // and regionserver both in the one JVM.
      if (LocalHBaseCluster.isLocal(conf)) {
        DefaultMetricsSystem.setMiniClusterMode(true);
        final MiniZooKeeperCluster zooKeeperCluster = new MiniZooKeeperCluster(conf);
        File zkDataPath = new File(conf.get(HConstants.ZOOKEEPER_DATA_DIR));

        // find out the default client port
        int zkClientPort = 0;

        // If the zookeeper client port is specified in server quorum, use it.
        String zkserver = conf.get(HConstants.ZOOKEEPER_QUORUM);
        if (zkserver != null) {
          String[] zkservers = zkserver.split(",");

          if (zkservers.length > 1) {
            // In local mode deployment, we have the master + a region server and zookeeper server
            // started in the same process. Therefore, we only support one zookeeper server.
            String errorMsg = "Could not start ZK with " + zkservers.length +
                " ZK servers in local mode deployment. Aborting as clients (e.g. shell) will not "
                + "be able to find this ZK quorum.";
              System.err.println(errorMsg);
              throw new IOException(errorMsg);
          }

          String[] parts = zkservers[0].split(":");

          if (parts.length == 2) {
            // the second part is the client port
            zkClientPort = Integer.parseInt(parts [1]);
          }
        }
        // If the client port could not be find in server quorum conf, try another conf
        if (zkClientPort == 0) {
          zkClientPort = conf.getInt(HConstants.ZOOKEEPER_CLIENT_PORT, 0);
          // The client port has to be set by now; if not, throw exception.
          if (zkClientPort == 0) {
            throw new IOException("No config value for " + HConstants.ZOOKEEPER_CLIENT_PORT);
          }
        }
        zooKeeperCluster.setDefaultClientPort(zkClientPort);
        // set the ZK tick time if specified
        int zkTickTime = conf.getInt(HConstants.ZOOKEEPER_TICK_TIME, 0);
        if (zkTickTime > 0) {
          zooKeeperCluster.setTickTime(zkTickTime);
        }

        // login the zookeeper server principal (if using security)
        ZKUtil.loginServer(conf, HConstants.ZK_SERVER_KEYTAB_FILE,
          HConstants.ZK_SERVER_KERBEROS_PRINCIPAL, null);
        int localZKClusterSessionTimeout =
          conf.getInt(HConstants.ZK_SESSION_TIMEOUT + ".localHBaseCluster", 10*1000);
        conf.setInt(HConstants.ZK_SESSION_TIMEOUT, localZKClusterSessionTimeout);
        LOG.info("Starting a zookeeper cluster");
        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.
        int mastersCount = conf.getInt("hbase.masters", 1);
        int regionServersCount = conf.getInt("hbase.regionservers", 1);
        // Set start timeout to 5 minutes for cmd line start operations
        conf.setIfUnset("hbase.master.start.timeout.localHBaseCluster", "300000");
        LOG.info("Starting up instance of localHBaseCluster; master=" + mastersCount +
          ", regionserversCount=" + regionServersCount);
        LocalHBaseCluster cluster = new LocalHBaseCluster(conf, mastersCount, regionServersCount,
          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;
}

ZK启动

ZK启动MiniZooKeeperCluster.startup(zkDataPath);
hbase ZK启动MiniZooKeeperCluster

zk的启动，主要逻辑在org.apache.zookeeper.server.NIOServerCnxnFactory
hbase NIOServerCnxnFactory

local HBase的启动（Master,RegionServer）以线程的方式
初始化一个LocalHBaseCluster，
org.apache.hadoop.hbase.LocalHBaseCluster
hbase LocalHBaseCluster

org.apache.hadoop.hbase.LocalHBaseCluster 实例化，可以看到下面调用了addMaster()、addRegionServer()
hbase LocalHBaseCluster

创建master线程

addMaster(),调用
JVMClusterUtil.createMasterThread创建master线程
创建master线程
hmc 即 org.apache.hadoop.hbase.master.HMasterCommandLine$LocalHMaster 对象
LocalHMaster extends HMaster
Master extends HRegionServer implements MasterServices
构造函数主要做了几件事情：1.初始化相关配置 2.初始化rpcServer 3.初始化zk监控类，下面看看一些具体的细节
1）在HRegionServer中会做初始化配置，检查