HDFS Using QJM
HA使用的是分布式的日志管理方式
一：概述
1.背景
如果namenode出現問題，整個HDFS集群將不能使用。
是不是可以有兩個namenode呢
一個為對外服務->active
一個處於待機->standby
他們的之間共享的元數據叫 nameservice
2.HDFS HA的幾大中重點
1）保證兩個namenode里面的內存中存儲的文件的元數據同步
->namenode啟動時，會讀鏡像文件
2）變化的記錄信息同步
3）日志文件的安全性
->分布式的存儲日志文件（cloudera公司提出來的）
->2n+1個，使用副本數保證安全性
->使用zookeeper監控
->監控兩個namenode，當一個出現了問題，可以達到自動故障轉移。
->如果出現了問題，不會影響整個集群
->zookeeper對時間同步要求比較高。
4）客戶端如何知道訪問哪一個namenode
->使用proxy代理
->隔離機制
->使用的是sshfence
->兩個namenode之間無密碼登錄
5）namenode是哪一個是active
->zookeeper通過選舉選出zookeeper。
->然后zookeeper開始監控，如果出現文件，自動故障轉移。
3.架構
注意兩個namenode之間的話。
4.使用QJM
JournalNode：日志節點，進程管理。
二：准備
3.規划集群
namenode namenode
journalnode journalnode journalnode -->日志的分布，這是日志節點，考慮的是日志的安全性。
datanode datanode datanode
4.關閉所有的進程
5.保存分布式的源數據，復制一份用來HDFS HA的檢測。
先是第一台，先將分布式的etc/hadoop，保存為dist-hadoop，保存源數據。
同時，新建tmp。
至於第二台以及第三台，在分發之間再進行配置。
三：配置文件
6.將core-site.xml中的文件系統刪除，並添加新的文件系統
以前的是使用是配置一台，現在配置多態namenode，使用的方式是nameservices的名稱的方式。
添加配置
7.配置hdfs-site.xml
8.繼續配置hdfs-site.xml
dfs.nameservices的配置
dfs.ha.namenodes.[nameservice ID]的配置
包括rpc，http的namenodde地址。
dfs.namenode.shared.edits.dir的配置
這是journalnode的地址
dfs.journalnode.edits.dir 的配置
這是journalnode的日志存儲的目錄
先新建目錄：
dfs.client.failover.proxy.provider的配置（客戶端）
dfs.ha.fencing.methods的配置
使用的方式為ssh攔截
9.配置完成，在分發之前先進行的是目錄的規划
10.分發
四：啟動
1.啟動三台zookeeper
現在有些奇怪，這三台zookeeper為啥要啟動，好像沒用到。
看視頻上啟動的，在這里暫時不啟動了，因為沒有用到，在自動故障轉移的時候才去使用。
2.啟動三台的日志節點
3.格式化第一台虛擬機
因為是共享數據，所以格式化一台虛擬機即可。
因為管理的是同一個元數據，所以另外一個不需要格式化。
4.啟動namenode（第一台）
5.緊接着，同步元數據（在第二台上寫命令）
最好是bin/hdfs namenode -help查看
6.啟動namenode（第兩台虛擬機）
7.啟動三台的datanode
8.觀看兩台的啟動狀態
關於這個問題，剛才在官網上看了一下，的確是啟動后會是兩個standby。
官網如下：
9.強制切換狀態
1）、查找幫助命令，屬於bin/hdfs haadmin
2）、具體命令
10.結果
1）、
或者：
這個查看第一台的狀態，也可以在第二台虛擬機上查看節點一，例如：
2）、
五：再次測試
1.在HDFS上新建目錄並上傳文件
2.殺死第一台的namenode，進行測試
3.將avtive的狀態切換到第二台
這個命令應該在第二台虛擬機上進行操作。
通過實驗發現，如果不進行強制轉換成active，這個命令是不會成功的，所以需要添加上--forceactive。
4.看第一台是否可以觀看hdfs中的文件
如果可以，說明，HA發揮作用了。
因為這時proxy提供的接口變成nn2.
六：自動故障轉移
前提：關閉所有的進程。
依賴：zookeeper的監控，組件為：ZKFC。
啟動以后都是standby，選舉一個active。
規划：
namenode namenode
ZKFC ZKFC
journalnode journalnode journalnode
datanode datanode datanode
1.看看官網的說法
這個地方關於zookeeper的使用不是太理解，需要到官網上研究一下。
還配置了一個zookeeper集群，用於ZKFC（DFSZKFailoverCont roller）故障轉移。
文章最后做一下說明。對ZKFC的原理。
2.配置core-site.xml
添加zookeeper的服務，包括主機名和端口號。
3.配置hdfs-site.xml
添加自動故障轉移的使能。
4.分發
5.確定關閉所有的進程
這一步是開始的基礎。
官網上的說法：
Before you begin configuring automatic failover, you should shut down your cluster. It is not currently possible to transition from a manual failover setup to an automatic failover setup while the cluster is running.
6.開啟三台的zookeeper服務
先開啟監控，然后方便下面進行初始化ZK，產生一個ZNode目錄。
7.初始化HA在zookeeper中的狀態bin/hdfs zkfc -formatZK
在zookepper上創建znode節點，用於存儲數據，方便自動實現故障轉移。
關於這個ZKFC的初始化需要在哪台虛擬機上進行，通過思考與實踐，在可以進行HA的那台機器上即可，而且做一次就行了。
在下面有說明情況。
8.觀察成功與否
進入zookeeper目錄
命令：bin/zkCli.sh
9.啟動sbin/start-dfs.sh
前兩台虛擬機會出現DFZKFailoverController。
如果沒有開啟DFZKFailoverController，可以手動開啟，命令是sbin/hadoop-daemon.sh start zkfc。
查看官網的說法：
七：簡單檢測
1.展示前兩台的虛擬機狀態
2.殺死第二台的虛擬機
3.結果
這時，第一台虛擬機變成active。
八：HA流程
1.說明
ZKGZ通過RPC協議獲取namenode的狀態
ZKFC連接zookeeper，完成選舉。
stabdby節點ZKFC監控本機的namenode。
ZKFC在監控周期內檢測到失效的namenode。
ZKFC記錄失敗的active namenode信息到zookeeper。
zookeeper發送一個通知給stabdby的節點ZKFC
standby節點ZKFC進入切換的流程，隔離剛才的主機。
ZKFC進行選舉，確保新的active節點。
九：ZKFC原理說明
1.基本原理
zk的基本特性：
(1) 可靠存儲小量數據且提供強一致性
(2) ephemeral node, 在創建它的客戶端關閉后，可以自動刪除
(3) 對於node狀態的變化，可以提供異步的通知(watcher)
zk在zkfc中可以提供的功能：
(1) Failure detector: 及時發現出故障的NN，並通知zkfc
(2) Active node locator: 幫助客戶端定位哪個是Active的NN
(3) Mutual exclusion of active state: 保證某一時刻只有一個Active的NN
2.模塊
(1) ZKFailoverController(DFSZKFailoverController): 驅動整個ZKFC的運轉，通過向HealthMonitor和ActiveStandbyElector注冊回調函數的方式，subscribe HealthMonitor和ActiveStandbyElector的事件，並做相應的處理
(2) HealthMonitor: 定期check NN的健康狀況，在NN健康狀況發生變化時，通過回調函數把變化通知給ZKFailoverController
(3) ActiveStandbyElector: 管理NN在zookeeper上的狀態，zookeeper上對應node的結點發生變化時，通過回調函數把變化通知給ZKFailoverController
(4) FailoverController: 提供做graceful failover的相關功能(dfs admin可以通過命令行工具手工發起failover)
3.架構
4.線程模型
ZKFC的線程模型總體上來講比較簡單的，它主要包括三類線程，一是主線程；一是HealthMonitor線程; 一是zookeeper客戶端的線程。它們的主要工作方式是：
(1) 主線程在啟動所有的服務后就開始循環等待
(2) HealthMonitor是一個單獨的線程，它定期向NN發包，檢查NN的健康狀況
(3) 當NN的狀態發生變化時，HealthMonitor線程會回調ZKFailoverController注冊進來的回調函數，通知ZKFailoverController NN的狀態發生了變化
(4) ZKFailoverController收到通知后，會調用ActiveStandbyElector的API，來管理在zookeeper上的結點的狀態
(5) ActiveStandbyElector會調用zookeeper客戶端API監控zookeeper上結點的狀態，發生變化時，回調ZKFailoverController的回調函數，通知ZKFailoverController，做出相應的變化
5.類關系圖
ZKFC的主類是org.apache.hadoop.hdfs.tools.DFSZKFailoverController。
6.formatZK
創建特定目錄，作為后續寫節點狀態的父路徑。如果該目錄已經存在，清理原有目錄為空目錄。
7.繼續說明
- HealthMonitor
在一個獨立線程中，通過RPC方式，周期性的調用HAServiceProtocol接口的monitorHealth方法，獲取NN的狀態。並把狀態報告給ActiveStandbyElector 。
- ActiveStandbyElector
ActiveStandbyElector 負責判斷哪個NN可以成為Active。它通過ZK，看哪個能夠成功的創建一個特定的ephemeral lock file (znode)，哪個就是Active，其它的成為Standby。在一個節點被通知變成Active后，它必須確保自己能夠提供一致性的服務（數據一致性），否則它需要主動退出選舉。
如果一個Active因HealthMonitor監控到狀態異常，這里會作出判斷，先通過Fenceing功能關閉它（確保關閉或者不能提供服務），然后在ZK上刪除它對應ZNode。
發送上述事件后，在另外一台機器上的ZKFC中的ActiveStandbyElector 會收到事件，並重新進行選舉（嘗試創建特定ZNode），它將獲得成功並更改NN中狀態，從而實現Active節點的變更。
十：formatZK日志說明
1.日志
18/01/28 19:48:30 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable 18/01/28 19:48:30 INFO tools.DFSZKFailoverController: Failover controller configured for NameNode NameNode at linux-hadoop01.ibeifeng.com/192.168.140.121:8020 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:zookeeper.version=3.4.6-1569965, built on 02/20/2014 09:09 GMT 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:host.name=linux-hadoop01.ibeifeng.com 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.version=1.7.0_67 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.vendor=Oracle Corporation 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.home=/opt/modules/jdk1.7.0_67/jre 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.class.path=/opt/fullyDistributions/ha/hadoop-2.5.0/etc/hadoop:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jackson-xc-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/httpcore-4.2.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jaxb-api-2.2.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/hamcrest-core-1.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/apacheds-i18n-2.0.0-M15.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/slf4j-api-1.7.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/activation-1.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/zookeeper-3.4.6.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-net-3.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-io-2.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/api-util-1.0.0-M20.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-compress-1.4.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jackson-jaxrs-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/xz-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/java-xmlbuilder-0.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-configuration-1.6.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jsp-api-2.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-math3-3.1.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/stax-api-1.0-2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/hadoop-annotations-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/guava-11.0.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jackson-mapper-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jackson-core-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/api-asn1-api-1.0.0-M20.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/httpclient-4.2.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/hadoop-auth-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-httpclient-3.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-codec-1.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jasper-compiler-5.5.23.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jets3t-0.9.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jettison-1.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jsch-0.1.42.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-collections-3.2.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jaxb-impl-2.2.3-1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jersey-server-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-lang-2.6.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/junit-4.11.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-digester-1.8.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/mockito-all-1.8.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/log4j-1.2.17.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/protobuf-java-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/servlet-api-2.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jersey-core-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/apacheds-kerberos-codec-2.0.0-M15.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jsr305-1.3.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jersey-json-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/paranamer-2.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/snappy-java-1.0.4.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-el-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-beanutils-1.7.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/slf4j-log4j12-1.7.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-cli-1.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/netty-3.6.2.Final.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/asm-3.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jetty-6.1.26.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jasper-runtime-5.5.23.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-beanutils-core-1.8.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/avro-1.7.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/commons-logging-1.1.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/xmlenc-0.52.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/lib/jetty-util-6.1.26.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/hadoop-common-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/hadoop-common-2.5.0-tests.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/common/hadoop-nfs-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-io-2.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jsp-api-2.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/guava-11.0.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jackson-mapper-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jackson-core-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-codec-1.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-daemon-1.0.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jersey-server-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-lang-2.6.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/log4j-1.2.17.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/protobuf-java-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/servlet-api-2.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jersey-core-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jsr305-1.3.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-el-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-cli-1.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/netty-3.6.2.Final.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/asm-3.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jetty-6.1.26.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jasper-runtime-5.5.23.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/commons-logging-1.1.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/xmlenc-0.52.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/lib/jetty-util-6.1.26.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/hadoop-hdfs-nfs-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/hadoop-hdfs-2.5.0-tests.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/hdfs/hadoop-hdfs-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jackson-xc-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jaxb-api-2.2.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jersey-client-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/activation-1.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/zookeeper-3.4.6.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-io-2.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-compress-1.4.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jackson-jaxrs-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/xz-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/leveldbjni-all-1.8.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/stax-api-1.0-2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/guava-11.0.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jackson-mapper-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/guice-servlet-3.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jackson-core-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-httpclient-3.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-codec-1.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jettison-1.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/aopalliance-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/guice-3.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-collections-3.2.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jaxb-impl-2.2.3-1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jersey-server-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-lang-2.6.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/log4j-1.2.17.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jersey-guice-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/protobuf-java-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/servlet-api-2.5.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jersey-core-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jsr305-1.3.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jersey-json-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/javax.inject-1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-cli-1.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/netty-3.6.2.Final.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/asm-3.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jetty-6.1.26.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jline-0.9.94.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/commons-logging-1.1.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/lib/jetty-util-6.1.26.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-applications-distributedshell-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-applications-unmanaged-am-launcher-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-server-tests-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-server-web-proxy-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-client-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-common-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-api-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-server-resourcemanager-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-server-nodemanager-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-server-common-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/yarn/hadoop-yarn-server-applicationhistoryservice-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/hamcrest-core-1.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/commons-io-2.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/commons-compress-1.4.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/xz-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/leveldbjni-all-1.8.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/hadoop-annotations-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/jackson-mapper-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/guice-servlet-3.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/jackson-core-asl-1.9.13.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/aopalliance-1.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/guice-3.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/jersey-server-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/junit-4.11.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/log4j-1.2.17.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/jersey-guice-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/protobuf-java-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/jersey-core-1.9.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/paranamer-2.3.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/snappy-java-1.0.4.1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/javax.inject-1.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/netty-3.6.2.Final.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/asm-3.2.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/lib/avro-1.7.4.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.5.0-tests.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-hs-plugins-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-common-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-shuffle-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-hs-2.5.0.jar:/opt/fullyDistributions/ha/hadoop-2.5.0/share/hadoop/mapreduce/hadoop-mapreduce-client-app-2.5.0.jar:/contrib/capacity-scheduler/*.jar 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.library.path=/opt/fullyDistributions/ha/hadoop-2.5.0/lib/native 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.io.tmpdir=/tmp 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:java.compiler=<NA> 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:os.name=Linux 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:os.arch=amd64 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:os.version=2.6.32-358.el6.x86_64 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:user.name=beifeng 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:user.home=/home/beifeng 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Client environment:user.dir=/opt/fullyDistributions/ha/hadoop-2.5.0 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Initiating client connection, connectString=linux-hadoop01.ibeifeng.com:2181,linux-hadoop02.ibeifeng.com:2181,linux-hadoop03.ibeifeng.com:2181 sessionTimeout=5000 watcher=org.apache.hadoop.ha.ActiveStandbyElector$WatcherWithClientRef@32dd803 18/01/28 19:48:31 INFO zookeeper.ClientCnxn: Opening socket connection to server linux-hadoop02.ibeifeng.com/192.168.140.122:2181. Will not attempt to authenticate using SASL (unknown error) 18/01/28 19:48:31 INFO zookeeper.ClientCnxn: Socket connection established to linux-hadoop02.ibeifeng.com/192.168.140.122:2181, initiating session 18/01/28 19:48:31 INFO zookeeper.ClientCnxn: Session establishment complete on server linux-hadoop02.ibeifeng.com/192.168.140.122:2181, sessionid = 0x2613c8b97f50000, negotiated timeout = 5000 18/01/28 19:48:31 INFO ha.ActiveStandbyElector: Successfully created /hadoop-ha/ns1 in ZK. 18/01/28 19:48:31 INFO zookeeper.ZooKeeper: Session: 0x2613c8b97f50000 closed 18/01/28 19:48:31 WARN ha.ActiveStandbyElector: Ignoring stale result from old client with sessionId 0x2613c8b97f50000 18/01/28 19:48:31 INFO zookeeper.ClientCnxn: EventThread shut down
2.作用
在倒數第四行有一行說法。
創建了一個目錄：
/hadoop-ha/ns1 in ZK
3.操作
上面有日志說connect 02虛擬機。
進入第二台zookeeper看看是否存在這個目錄。
