启动NameServer,代码入口是NamesrvController#initialize

public boolean initialize() {
  //加载kvConfigPath下kvConfig.json配置文件里的KV配置，然后将这些配置放到KVConfigManager#configTable属性中
    this.kvConfigManager.load();
  //根据nettyServerConfig初始化一个netty服务器。
    //brokerHousekeepingService是在NamesrvController实例化时构造函数里实例化的，该类负责Broker连接事件的处理，实现了ChannelEventListener，主要用来管理RouteInfoManager的brokerLiveTable
    this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService);
  //初始化负责处理Netty网络交互数据的线程池，默认线程数是8个
    this.remotingExecutor =
        Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_"));
  //注册Netty服务端业务处理逻辑，如果开启了clusterTest，那么注册的请求处理类是ClusterTestRequestProcessor，否则请求处理类是DefaultRequestProcessor
    this.registerProcessor();
  //注册心跳机制线程池，延迟5秒启动，每隔10秒遍历RouteInfoManager#brokerLiveTable这个属性，用来扫描不存活的broker
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
​
        @Override
        public void run() {
            NamesrvController.this.routeInfoManager.scanNotActiveBroker();
        }
    }, 5, 10, TimeUnit.SECONDS);
  //注册打印KV配置线程池，延迟1分钟启动、每10分钟打印出kvConfig配置
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
​
        @Override
        public void run() {
            NamesrvController.this.kvConfigManager.printAllPeriodically();
        }
    }, 1, 10, TimeUnit.MINUTES);
  //rocketmq可以通过开启TLS来提高数据传输的安全性，如果开启了，那么需要注册一个监听器来重新加载SslContext
    if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
        // Register a listener to reload SslContext
        try {
            fileWatchService = new FileWatchService(
                new String[] {
                    TlsSystemConfig.tlsServerCertPath,
                    TlsSystemConfig.tlsServerKeyPath,
                    TlsSystemConfig.tlsServerTrustCertPath
                },
                new FileWatchService.Listener() {
                    boolean certChanged, keyChanged = false;
                    @Override
                    public void onChanged(String path) {
                        if (path.equals(TlsSystemConfig.tlsServerTrustCertPath)) {
                            log.info("The trust certificate changed, reload the ssl context");
                            reloadServerSslContext();
                        }
                        if (path.equals(TlsSystemConfig.tlsServerCertPath)) {
                            certChanged = true;
                        }
                        if (path.equals(TlsSystemConfig.tlsServerKeyPath)) {
                            keyChanged = true;
                        }
                        if (certChanged && keyChanged) {
                            log.info("The certificate and private key changed, reload the ssl context");
                            certChanged = keyChanged = false;
                            reloadServerSslContext();
                        }
                    }
                    private void reloadServerSslContext() {
                        ((NettyRemotingServer) remotingServer).loadSslContext();
                    }
                });
        } catch (Exception e) {
            log.warn("FileWatchService created error, can't load the certificate dynamically");
        }
    }
​
    return true;
}