namenode启动时候都做了什么

1.	NameNode.main(): 
NameNode namenode = createNameNode(argv, null);
2.	NameNode. createNameNode():
setStartupOption(conf, startOpt);
		// conf.set("dfs.namenode.startup", opt.toString());
NameNode namenode = new NameNode(conf);
	// initialize(conf);
3.	initialize(conf);
InetSocketAddress socAddr = NameNode.getAddress(conf);
		//根据配置文件中fs.default.name的值建立InetSocketAddress
int handlerCount = conf.getInt("dfs.namenode.handler.count", 10);
		//获取hdfs-site.xml中配置的dfs.namenode.handler.count值
// set service-level authorization security policy
		//这段没看懂。。
this.server = RPC.getServer(this, socAddr.getHostName(), socAddr.getPort(),handlerCount, false, conf);
		//建立RPC server
startHttpServer(conf);
		//建立httpServer
this.server.start();  
//start RPC server
startTrashEmptier(conf);
	//回收站处理进程