Hadoop基础教程-第9章 HA高可用（9.2 HDFS 高可用配置）（草稿）

第9章 HA高可用

9.2 HDFS 高可用配置

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9.2.1 准备工作

因为前面我们已经配置启动了普通的Hadoop相关服务，需要先停止相关服务并清除数据。
（1）停止Hadoop服务
首先停止YARN

[root@node1 ~]# stop-yarn.shstopping yarn daemonsstopping resourcemanagernode2: stopping nodemanagernode3: stopping nodemanagernode1: stopping nodemanagernode2: nodemanager did not stop gracefully after 5 seconds: killing with kill -9node3: nodemanager did not stop gracefully after 5 seconds: killing with kill -9node1: nodemanager did not stop gracefully after 5 seconds: killing with kill -9no proxyserver to stop

停止HDFS服务

[root@node1 ~]# stop-dfs.shStopping namenodes on [node1]node1: stopping namenodenode3: stopping datanodenode1: stopping datanodenode2: stopping datanodeStopping secondary namenodes [node2]node2: stopping secondarynamenode[root@node1 ~]# 

（2）删除HDFS数据

[root@node1 ~]# rm -rf /var/data/hadoop[root@node2 ~]# rm -rf /var/data/hadoop[root@node3 ~]# rm -rf /var/data/hadoop

[root@node1 ~]# rm -rf /tmp/*[root@node2 ~]# rm -rf /tmp/*[root@node3 ~]# rm -rf /tmp/*

（3）准备zookeeper
启动Zookeeper集群。在每个节点上启动Zookeeper服务并确定状态正确
node1

[root@node1 ~]# jps6117 Jps2623 QuorumPeerMain[root@node1 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /opt/zookeeper-3.4.10/bin/../conf/zoo.cfgMode: follower[root@node1 ~]# 

node2

[root@node2 ~]# jps3632 Jps2354 QuorumPeerMain[root@node2 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /opt/zookeeper-3.4.10/bin/../conf/zoo.cfgMode: leader[root@node2 ~]# 

node3

[root@node3 ~]# jps2278 QuorumPeerMain3277 Jps[root@node3 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /opt/zookeeper-3.4.10/bin/../conf/zoo.cfgMode: follower[root@node3 ~]# 

实际上，上面命令执行过程是：
(1)通过XShell执行zkServer.sh start
(2)等待1到2秒，再通过通过XShell执行zkServer.sh status

9.2.2 core-site.xml配置

[root@node1 ~]# cd /opt/hadoop-2.7.3/etc/hadoop/[root@node1 hadoop]# vi core-site.xml 

编辑内容如下，

[root@node1 hadoop]# cat core-site.xml <?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="configuration.xsl"?><configuration>    <property>        <name>fs.defaultFS</name>        <value>hdfs://cetc</value>        <description>默认路径前缀</description>    </property>    <property>        <name>hadoop.tmp.dir</name>        <value>/hadoop</value>        <description>Hadoop临时目录</description>    </property>    <property>        <name>io.file.buffer.size</name>        <value>65536</value>        <description>序列文件的缓冲区的大小</description>    </property>    <property>        <name>dfs.ha.fencing.methods</name>        <value>            sshfence            shell(/bin/true)        </value>        <description>配置隔离机制,多个机制用换行分割</description>    </property>    <property>        <name>dfs.ha.fencing.ssh.private-key-files</name>        <value>/root/.ssh/id_rsa</value>        <description>使用隔离机制时需要ssh免登录</description>    </property>    <property>        <name>ha.zookeeper.quorum</name>        <value>node1:2181,node2:2181,node2:2181</value>        <description>由ZKFC在自动故障转移中使用的ZooKeeper列表</description>    </property></configuration>

提醒：一些教程将dfs.ha.fencing.methods和dfs.ha.fencing.ssh.private-key-files属性配置在hdfs-site.xml文件中。通过查看官方文件http://hadoop.apache.org/docs/r2.7.3/hadoop-project-dist/hadoop-common/core-default.xml 和 http://hadoop.apache.org/docs/r2.7.3/hadoop-project-dist/hadoop-hdfs/hdfs-default.xml，发现这两个属性应该在core-site.xml文件进行配置，而非hdfs-site.xml。

9.2.3 hdfs-site.xml配置

[root@node1 hadoop]# vi hdfs-site.xml [root@node1 hadoop]# cat hdfs-site.xml <?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="configuration.xsl"?><configuration>    <property>        <name>dfs.nameservices</name>        <value>cetc</value>        <description>名称服务的逻辑名称</description>    </property>    <property>        <name>dfs.ha.namenodes.cetc</name>        <value>nn1,nn2</value>        <description>名称服务中每个NameNode的唯一标识符</description>    </property>    <property>        <name>dfs.namenode.rpc-address.cetc.nn1</name>        <value>node1:8020</value>        <description>每个NameNode要监听的完全限定的RPC地址</description>    </property>    <property>        <name>dfs.namenode.rpc-address.cetc.nn2</name>        <value>node2:8020</value>        <description>每个NameNode要监听的完全限定的RPC地址</description>    </property>    <property>        <name>dfs.namenode.http-address.cetc.nn1</name>        <value>node1:50070</value>        <description>每个NameNode要监听的完全限定的HTTP地址</description>    </property>    <property>        <name>dfs.namenode.http-address.cetc.nn2</name>        <value>node2:50070</value>        <description>每个NameNode要监听的完全限定的HTTP地址</description>    </property>    <property>        <name>dfs.namenode.shared.edits.dir</name>        <value>qjournal://node1:8485;node2:8485;node3:8485/abc</value>        <description>HA群集中多个节点之间的共享存储上的目录。</description>    </property>    <property>        <name>dfs.journalnode.edits.dir</name>        <value>/hadoop/journalnode</value>        <description>指定JournalNode在本地磁盘存放数据的位置</description>    </property>    <property>        <name>dfs.ha.automatic-failover.enabled</name>        <value>true</value>        <description>启用namenode自动切换</description>    </property>    <property>        <name>dfs.client.failover.proxy.provider.cetc</name>        <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>        <description>NameNode自动切换实现方式</description>    </property>    <property>        <name>dfs.replication</name>        <value>3</value>        <description>副本数</description>    </property></configuration>[root@node1 hadoop]# 

提醒：
请注意检查参数，别写错了。比如单词写错，很难检查出来。

9.2.4 配置hadoop-env.sh

[root@node1 hadoop]# vi hadoop-env.sh

修改两处

export JAVA_HOME=/opt/jdk1.8.0_112

export HADOOP_PID_DIR=/var/run

注意，如果设置了export HADOOP_PID_DIR=/var/run/hadoop，需要创建/var/run/hadoop目录。

9.2.4 分发配置文件

因为node2和node3节点上已经存在hadoop软件包，只需要向这两个节点分发配置文件即可。

[root@node1 hadoop]# scp core-site.xml node2:/opt/hadoop-2.7.3/etc/hadoop/core-site.xml                                                                                                                                              100% 1003     1.0KB/s   00:00    [root@node1 hadoop]# scp hdfs-site.xml node2:/opt/hadoop-2.7.3/etc/hadoop/hdfs-site.xml                                                                                                                                              100% 2434     2.4KB/s   00:00    [root@node1 hadoop]# scp core-site.xml node3:/opt/hadoop-2.7.3/etc/hadoop/core-site.xml                                                                                                                                              100% 1003     1.0KB/s   00:00    [root@node1 hadoop]# scp hdfs-site.xml node3:/opt/hadoop-2.7.3/etc/hadoop/hdfs-site.xml                                                                                                                                              100% 2434     2.4KB/s   00:00    [root@node1 hadoop]# scp hadoop-env.sh node2:/opt/hadoop-2.7.3/etc/hadoop/hadoop-env.sh                                                                                                                                              100% 4227     4.1KB/s   00:00    [root@node1 hadoop]# scp hadoop-env.sh node3:/opt/hadoop-2.7.3/etc/hadoop/hadoop-env.sh                                                                                                                                              100% 4227     4.1KB/s   00:00    [root@node1 hadoop]#