From adba43d1540019c105c24e97849647d42e130d04 Mon Sep 17 00:00:00 2001
From: zeekling <lingzhaohui@zeekling.cn>
Date: Sat, 12 Oct 2024 00:25:56 +0800
Subject: [PATCH] =?UTF-8?q?=E5=A2=9E=E5=8A=A0Router=E8=AF=A6=E8=A7=A3?=
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---
 hdfs/router启动详解.md | 41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/hdfs/router启动详解.md b/hdfs/router启动详解.md
index d2f4b19..898c747 100644
--- a/hdfs/router启动详解.md
+++ b/hdfs/router启动详解.md
@@ -9,7 +9,9 @@
 
 # 子模块
 
-## State Store模块
+## 一、State Store模块
+
+当前模块主要用于保存Router状态信息，提供了文件系统(HDFS、本地)、Mysql、Zookeeper。个人觉得一般使用Zookeeper比较合理。
 
 ### 初始化
 
@@ -149,7 +151,7 @@ MySQLStateStoreHikariDataSourceConnectionFactory(Configuration conf) {
 
 ##### initRecordStorage
 
-zai StateStoreMySQLImpl当中，每个state store 对应一张表。建表语句如下：
+在StateStoreMySQLImpl当中，每个state store 对应一张表。建表语句如下：
 ```sql
 CREATE TABLE <className> (
    recordKey VARCHAR (255) NOT NULL,
@@ -163,10 +165,43 @@ CREATE TABLE <className> (
 
 ##### initDriver
 
+对于StateStoreZooKeeperImpl，initDriver中主要是建立zk连接。核心代码如下：
+```java
+this.zkManager = new ZKCuratorManager(conf);
+this.zkManager.start(zkHostPort);
+this.zkAcl = ZKCuratorManager.getZKAcls(conf);
+```
+对于异步模式，会创建线程池，用于异步保存状态。
+```java
+ThreadFactory threadFactory = new ThreadFactoryBuilder()
+    .setNameFormat("StateStore ZK Client-%d")
+    .build();
+this.executorService = new ThreadPoolExecutor(numThreads, numThreads,
+    0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(), threadFactory);
+LOG.info("Init StateStoreZookeeperImpl by async mode with {} threads.", numThreads);
+```
+
 ##### initRecordStorage
 
+当前函数的实现比较简单，主要是在zk上面创建状态保存的目录。
+```java
+try {
+  String checkPath = getNodePath(baseZNode, className);
+  zkManager.createRootDirRecursively(checkPath, zkAcl);
+  return true;
+} catch (Exception e) {
+  LOG.error("Cannot initialize ZK node for {}: {}",
+      className, e.getMessage());
+  return false;
+}
+```
+
+## 二、ActiveNamenodeResolver
+具体实现有配置项dfs.federation.router.namenode.resolver.client.class指定。默认为MembershipNamenodeResolver.class。目前最新的也只支持这一种。
+
+### MembershipNamenodeResolver
+
 
-## ActiveNamenodeResolver
 
 
 ## subclusterResolver