為什么80%的碼農都做不了架構師？>>> ??

? ? ?上篇實戰了HDFS的HA方案，這篇來實戰一下MRv1的HA方案，還是基于上篇的環境來實戰，原有的HDFS HA環境不做拆除。因為Jobtracker的HA和non-HA架構不能同時存在于一個集群中，所以如果要實施Jobtracker HA，則需要卸載non-HA的Jobtracker的配置。

CDH4.5 Hadoop集群信息如下

192.168.1.10 U-1 Active-NameNode zkfc JobtrackerHA mapreduce-zkfc 192.168.1.20 U-2 DataNode zookeeper journalnode 192.168.1.30 U-3 DataNode zookeeper journalnode 192.168.1.40 U-4 DataNode zookeeper journalnode 192.168.1.50 U-5 DataNode 192.168.1.70 U-7 Standby-NameNode zkfc JobtrackerHA mapreduce-zkfc 1? ? 卸載U-1上的non-HA Jobtracker安裝包

service hadoop-0.20-mapreduce-tasktracker stop service hadoop-0.20-mapreduce-jobtracker stop apt-get --purge remove hadoop-0.20-mapreduce-jobtracker 2? ? 在U-1/7上安裝JobtrackerHA包

apt-get install hadoop-0.20-mapreduce-jobtrackerha

3? ? 因為我們要利用zookeeper做自動故障轉移，所以需要在U-1/7上安裝Jobtracker的zkfc包

apt-get install hadoop-0.20-mapreduce-zkfc

4? ? 配置Jobtracker的HA配置文件(mapred-site.xml)

?????????在集群中的每個JobTracker都有不同的JobTracker ID，用來支持一個配置文件適合所有的JobTracker，所以我們照樣選擇myjob作為我們的ID。

<configuration> <property><name>mapred.job.tracker</name><value>myjob</value> </property><property><name>mapred.jobtrackers.myjob</name><value>U-1,U-7</value> </property><property><name>mapred.jobtracker.rpc-address.myjob.U-1</name><value>U-1:8021</value> </property><property><name>mapred.jobtracker.rpc-address.myjob.U-7</name><value>U-7:8022</value> </property><property><name>mapred.job.tracker.http.address.myjob.U-1</name><value>U-1:50030</value> </property><property><name>mapred.job.tracker.http.address.myjob.U-7</name><value>U-7:50031</value> </property><property><name>mapred.ha.jobtracker.rpc-address.myjob.U-1</name><value>U-1:8023</value> </property><property><name>mapred.ha.jobtracker.rpc-address.myjob.U-7</name><value>U-7:8024</value> </property><property><name>mapred.ha.jobtracker.http-redirect-address.myjob.U-1</name><value>U-1:50032</value> </property><property><name>mapred.ha.jobtracker.http-redirect-address.myjob.U-7</name><value>U-7:50033</value> </property><property><name>mapred.local.dir</name><value>/mapred</value> </property><property><name>mapreduce.jobtracker.restart.recover</name><value>true</value> </property><property><name>mapred.job.tracker.persist.jobstatus.active</name><value>true</value> </property><property><name>mapred.job.tracker.persist.jobstatus.hours</name><value>1</value> </property><property><name>mapred.job.tracker.persist.jobstatus.dir</name><value>/jobtracker</value> </property><property><name>mapred.client.failover.proxy.provider.logicaljt</name><value>org.apache.hadoop.mapred.ConfiguredFailoverProxyProvider</value> </property><property><name>mapred.client.failover.max.attempts</name><value>15</value> </property><property><name>mapred.client.failover.sleep.base.millis</name><value>500</value> </property><property><name>mapred.client.failover.sleep.max.millis</name><value>1500</value> </property><property><name>mapred.client.failover.connection.retries</name><value>0</value> </property><property><name>mapred.client.failover.connection.retries.on.timeouts</name><value>0</value> </property><property><name>mapred.ha.fencing.methods</name><value>sshfence</value> </property><property><name>dfs.ha.fencing.ssh.private-key-files</name><value>/usr/lib/hadoop-0.20-mapreduce/.ssh/id_rsa</value> </property><property><name>mapred.ha.automatic-failover.enabled</name><value>true</value> </property><property><name>mapred.ha.zkfc.port</name><value>8018</value> </property> </configuration> 5? ? 把mapred-site.xml文件拷貝到U-2/3/4/5/7上相同的目錄下，不過在CDH4.5中有個坑啊，官方文檔中明確的說明mapred.job.tracker的值在HA模式下是一個不能帶端口的字符串ID。

????In an HA setup, the logical name of the JobTracker active-standby pair. In a non-HA setup mapred.job.tracker is a host:port string specifying the JobTracker's RPC address, but in an HA configuration the logical name must not include a port number. ????? ? 拷貝到U-2/3/4/5之后，TaskTracker直接起不來，日志報如下?

2014-05-22 18:56:10,119 ERROR org.apache.hadoop.mapred.TaskTracker: Can not start task tracker because java.lang.IllegalArgumentException: Does not contain a valid host:port authority: myjobat org.apache.hadoop.net.NetUtils.createSocketAddr(NetUtils.java:210)at org.apache.hadoop.net.NetUtils.createSocketAddr(NetUtils.java:162)at org.apache.hadoop.net.NetUtils.createSocketAddr(NetUtils.java:151)at org.apache.hadoop.mapred.JobTrackerProxies.createProxy(JobTrackerProxies.java:76)at org.apache.hadoop.mapred.TaskTracker.initialize(TaskTracker.java:1065)at org.apache.hadoop.mapred.TaskTracker.<init>(TaskTracker.java:1780)at org.apache.hadoop.mapred.TaskTracker.main(TaskTracker.java:4123) ????? ? 然后把U-2/3/4/5的配置改成如下?

<property><name>mapred.job.tracker</name><value>myjob:8021</value> </property> ????? ? 然后TaskTracker是可以啟動了，可是到日志里面一看?

2014-05-22 18:55:04,114 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: myjob/180.168.41.175:8021. Already tried 9 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS) 2014-05-22 18:55:04,119 ERROR org.apache.hadoop.mapred.TaskTracker: Caught exception: java.net.ConnectException: Call From U-4/192.168.1.40 to myjob:8021 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefusedat sun.reflect.GeneratedConstructorAccessor5.newInstance(Unknown Source)at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)at java.lang.reflect.Constructor.newInstance(Constructor.java:526)at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:782)at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:729)at org.apache.hadoop.ipc.Client.call(Client.java:1242)at org.apache.hadoop.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:225)at org.apache.hadoop.mapred.$Proxy9.getBuildVersion(Unknown Source)at org.apache.hadoop.mapred.TaskTracker.offerService(TaskTracker.java:1958)at org.apache.hadoop.mapred.TaskTracker.run(TaskTracker.java:2875)at org.apache.hadoop.mapred.TaskTracker.main(TaskTracker.java:4125) Caused by: java.net.ConnectException: Connection refused

????? ? 這各真是坑爹.....?

6? ? 重啟zookeeper服務(U-2/3/4)

service zookeeper-server restart 7? ? 初始化mapreduce-zkfc(U-1)

service hadoop-0.20-mapreduce-zkfc init 8? ? 啟動mapreduce-zkfc服務(U-1/7)

service hadoop-0.20-mapreduce-zkfc start 9? ? 啟動mapreduce-jobtrackerha服務

service hadoop-0.20-mapreduce-jobtrackerha start 10? ?我們看看U-1/3/5/7上面跑了哪些相關進程

11? ? 查看U-1/7上的JobTracker各處于什么狀態

12? ? 我們模擬一次故障轉換

13? ? kill掉U-7上面的JobTrackerHADaemon

轉載于:https://my.oschina.net/guol/blog/267789

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