hdfs/nameNode启动过程.md

@@ -153,6 +153,7 @@ private void startCommonServices(Configuration conf) throws IOException {
   // 启动所有插件
   for (ServicePlugin p: plugins) {
     try {
+      // 调用插件的start接口，需要插件自己实现，需要实现接口ServicePlugin
       p.start(this);
     } catch (Throwable t) {
       LOG.warn("ServicePlugin " + p + " could not be started", t);
@@ -202,8 +203,7 @@ void startCommonServices(Configuration conf, HAContext haContext) throws IOExcep
   // 注册快照管理器
   snapshotManager.registerMXBean();
   InetSocketAddress serviceAddress = NameNode.getServiceAddress(conf, true);
-  this.nameNodeHostName = (serviceAddress != null) ?
-      serviceAddress.getHostName() : "";
+  this.nameNodeHostName = (serviceAddress != null) ? serviceAddress.getHostName() : "";
 }
 ```
 
@@ -219,6 +219,7 @@ void startCommonServices(Configuration conf, HAContext haContext) throws IOExcep
 ```java 
 public void activate(Configuration conf, long blockTotal) {
   pendingReconstruction.start();
+  // 初始化datanodeManager
   datanodeManager.activate(conf);
   this.redundancyThread.setName("RedundancyMonitor");
   this.redundancyThread.start();
@@ -231,5 +232,3 @@ public void activate(Configuration conf, long blockTotal) {
 ```
 
 
-
-