Take you quickly set up a Hadoop cluster HA!

        I believe after reading a previous blog "takes you quickly recognize NamenodeHA and Yarn HA, lay the foundation for building HadoopHA cluster!" After, we must respect very much looking forward how to build HA cluster 9 (1❛ᴗ❛1) 6 not panic, this blog post will bring a detailed tutorial to build HA cluster for everyone!

        Codeword is not easy, praise after the first look!

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Build Hadoop HA Cluster

friendly reminder

        All the following operations are performed there on the basis of a Hadoop cluster . We recommend that you first install the cluster friends to see this blog "Hadoop (CDH) to build a distributed environment" , to build up a normal cluster available, look at this blog "zookeeper Detailed installation" installed on the cluster and then look at the Zookeeper this advanced blog.

<1> Hadoop cluster installation configuration

① Backup Cluster

        Because we had already built a good cluster, so we need before the first cluster hadoop closed .
        stop-all.sh

        Then hadoop directory where the previous backup (three nodes)

        cd /export/servers/

        mv mv hadoop-2.6.0-cdh5.14.0 hadoop-2.6.0-cdh5.14.0_bk

② extract the new cluster

        Hadoop into the directory where the installation package, re-extract.

        cd /export/softwares/

        tar -zxvf hadoop-2.6.0-cdh5.14.0.tar.gz -C ../servers/

③ Configuring HDFS

Note that, hadoop2.0 all configuration files are in the $ HADOOP_HOME / etc / hadoop directory

This step was supposed to do operations like adding some of the system environment variables, but because we are before the cluster has been completed these operations, so this step can skip the content - which is why I recommend you first good reason to build a cluster.

④ modify the core-site.xml

        Into the specified directory:

        cd /export/servers/hadoop-2.6.0-cdh5.14.0/etc/hadoop

        Edit core-site.xml, add the following configuration

        vim core-site.xml

<configuration>
<!-- 集群名称在这里指定！该值来自于hdfs-site.xml中的配置 -->
<property>
<name>fs.defaultFS</name>
<value>hdfs://cluster1</value>
</property>
<!-- 这里的路径默认是NameNode、DataNode、JournalNode等存放数据的公共目录 -->
<property>
<name>hadoop.tmp.dir</name>
<value>/export/servers/hadoop-2.6.0-cdh5.14.0/HAhadoopDatas/tmp</value>
</property>

<!-- ZooKeeper集群的地址和端口。注意，数量一定是奇数，且不少于三个节点-->
<property>
<name>ha.zookeeper.quorum</name>
<value>node01:2181,node02:2181,node03:2181</value>
</property>
</configuration>

⑤ modify hdfs-site.xml

        vim hdfs-site.xml

<configuration>
<!--指定hdfs的nameservice为cluster1，需要和core-site.xml中的保持一致 -->
<property>
<name>dfs.nameservices</name>
<value>cluster1</value>
</property>
<!-- cluster1下面有两个NameNode，分别是nn1，nn2 -->
<property>
<name>dfs.ha.namenodes.cluster1</name>
<value>nn1,nn2</value>
</property>
<!-- nn1的RPC通信地址 -->
<property>
<name>dfs.namenode.rpc-address.cluster1.nn1</name>
<value>node01:8020</value>
</property>
<!-- nn1的http通信地址 -->
<property>
<name>dfs.namenode.http-address.cluster1.nn1</name>
<value>node01:50070</value>
</property>
<!-- nn2的RPC通信地址 -->
<property>
<name>dfs.namenode.rpc-address.cluster1.nn2</name>
<value>node02:8020</value>
</property>
<!-- nn2的http通信地址 -->
<property>
<name>dfs.namenode.http-address.cluster1.nn2</name>
<value>node02:50070</value>
</property>
<!-- 指定NameNode的edits元数据在JournalNode上的存放位置 -->
<property>
<name>dfs.namenode.shared.edits.dir</name>
<value>qjournal://node01:8485;node02:8485;node03:8485/cluster1</value>
</property>
<!-- 指定JournalNode在本地磁盘存放数据的位置 -->
<property>
<name>dfs.journalnode.edits.dir</name>
<value>/export/servers/hadoop-2.6.0-cdh5.14.0/journaldata</value>
</property>
<!-- 开启NameNode失败自动切换 -->
<property>
<name>dfs.ha.automatic-failover.enabled</name>
<value>true</value>
</property>
<!-- 指定该集群出故障时，哪个实现类负责执行故障切换 -->
<property>
<name>dfs.client.failover.proxy.provider.cluster1</name>
<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
</property>
<!-- 配置隔离机制方法，多个机制用换行分割，即每个机制暂用一行-->
<property>
<name>dfs.ha.fencing.methods</name>
<value>
sshfence
</value>
</property>
<!-- 使用sshfence隔离机制时需要ssh免登陆 -->
<property>
<name>dfs.ha.fencing.ssh.private-key-files</name>
<value>/root/.ssh/id_rsa</value>
</property>
<!-- 配置sshfence隔离机制超时时间 -->
<property>
<name>dfs.ha.fencing.ssh.connect-timeout</name>
<value>30000</value>
</property>
</configuration>

⑦ modify mapred-site.xml

        A first backup
        cp mapred-site.xml.template mapred-site.xml

        Edit mapred-site.xml, add the following

<configuration>
<!-- 指定mr框架为yarn方式 -->
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>

⑧ modified yarn-site.xml

        Modify yarn-site.xml, add the following:

        vim yarn-site.xml

<configuration>
<!-- 开启RM高可用 -->
<property>
<name>yarn.resourcemanager.ha.enabled</name>
<value>true</value>
</property>
<!-- 指定RM的cluster id -->
<property>
<name>yarn.resourcemanager.cluster-id</name>
<value>yrc</value>
</property>
<!-- 指定RM的名字 -->
<property>
<name>yarn.resourcemanager.ha.rm-ids</name>
<value>rm1,rm2</value>
</property>
<!-- 分别指定RM的地址 -->
<property>
<name>yarn.resourcemanager.hostname.rm1</name>
<value>node01</value>
</property>
<property>
<name>yarn.resourcemanager.hostname.rm2</name>
<value>node02</value>
</property>
<!-- 指定zk集群地址 -->
<property>
<name>yarn.resourcemanager.zk-address</name>
<value>node01:2181,node02:2181,node03:2181</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
</configuration>

⑨ modify slaves

vim slaves

node01
node02
node03

        Copying the software to all nodes

        Here scp command is, of course, xsyncbut possible -

        scp -r hadoop-2.6.0-cdh5.14.0 node02:/$PWD
        scp -r hadoop-2.6.0-cdh5.14.0 node03:/$PWD

⑩ configuration-free dense Login

        It should be on the standby node configuration-free dense logged in, but since when we install the original cluster has been configured, so this step can be skipped ~

# First, configure node01 to node01, node02, node03 the password-free login
# produce a pair of keys on node01
SSH-keygen
# copy the public key to other nodes, including their own
SSH-coyp-the above mentioned id node01
SSH-coyp-the above mentioned id node02
SSH node03 the above mentioned id--coyp
# Note: between two namenode to configure ssh ssh remote login password-free up the knife when needed
# node02 in the production of a pair of keys
ssh-keygen
# copy the public key to node01
ssh-coyp-the above mentioned id node01

<2> to start the process

        In strict accordance with the following procedure, or we can not guarantee success

① start zookeeper cluster

        Start zookeeper respectively on node01, node02, node03 node

bin/zkServer.sh start
#查看状态：一个leader，两个follower
bin/zkServer.sh status

② manually start journalnode

        Respectively executed on node01, node02, node03

hadoop-daemon.sh start journalnode
#运行jps命令检验，node01、node02、node03上多了JournalNode进程

③ formatting namenode

#在node01上执行命令:
hdfs namenode -format
#格式化后会在根据core-site.xml中的hadoop.tmp.dir配置的目录下生成个hdfs初始化文件，
			
hadoop.tmp.dir配置的目录下所有文件拷贝到另一台namenode节点所在的机器
scp -r tmp/ node02:/home/hadoop/app/hadoop-2.6.4/

④ format ZKFC (can be performed on the active)

hdfs zkfc -formatZK

⑤ start HDFS (executed on node01)

start-dfs.sh

⑥ start YARN

start-yarn.sh
还需要手动在standby上手动启动备份的  resourcemanager
yarn-daemon.sh start resourcemanager

<3> Browser Access

        After configuring the above, with a jpsview of the current process

[root@node01 helloworld]# jps
14305 QuorumPeerMain
15186 NodeManager
14354 JournalNode
14726 DataNode
20887 Jps
15096 ResourceManager
15658 NameNode
14991 DFSZKFailoverController

Finally you can access the browser -

Access node01
http://node01:50070

It can be found in the current state of the node namenodeActive

Access node02

http://node02:50070

You can find the current state of the node namenode to (standby)

illustrate the deployment of our HA cluster success ~

Next we upload a file to hdfs
hadoop fs -put /etc/profile /profile

Through the UI interface you can see the new file upload will come up

Then kill off the active node status (ie node01) of NameNode

kill -9 <pid of NN>

This time we visited by node02 browser
http://node02:50070

After the discovery node01 "down", node02 namenode in the Activestate!

Run the following command on node02 node, the data can be found in clusters with former node01 downtime is the same.

hadoop fs -ls /
-rw-r--r--   3 root supergroup       1926 2014-02-06 15:36 /profile

We just manually "kill" the namenode on node01 node, and now we start it manually.

hadoop-daemon.sh start namenode

Front verify the HA, and now we look to authenticate Yarn!

Any node, run the demo hadoop WordCount program offered in:

hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0-cdh5.14.0.jar wordcount /profile /out

See above renderings, that we build the HA cluster considered a success !!!

<4> expand

OK and you're done! Here expand some test HA cluster command

hdfs dfsadmin -report	 查看hdfs的各节点状态信息

hdfs haadmin -getServiceState nn1  获取一个namenode节点的HA状态

hadoop-daemon.sh start zkfc   单独启动一个zkfc进程

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