HDFS ViewFs配置

1.      core-site.xml文件

<configuration  xmlns:xi="http://www.w3.org/2001/XInclude">
<xi:includehref="mountTable.xml" />
        <property>
          <name>fs.defaultFS</name>
         <value>viewfs://mycluster</value>
        </property>
        <property>
         <name>dfs.journalnode.edits.dir</name>
         <value>/home/hihadoop/hadoop/jns</value>
        </property>
        <property>
         <name>hadoop.tmp.dir</name>
         <value>/hadoop/tmp</value>
        </property>
        <property>
           <name>ha.zookeeper.quorum</name>
          <value>hadoopa.highgo.com:2181</value>
           </property>
</configuration>

2.      mountTable.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheettype="text/xsl" href="configuration.xsl"?>
<configuration>
  <property>
      <name>fs.viewfs.mounttable.mycluster.homedir</name>
          <value>/home</value>
      </property>
       <property>
                 <name>fs.viewfs.mounttable.mycluster.link./home</name>
                      <value>hdfs://ns1/home</value>
       </property>
       <property>
             <name>fs.viewfs.mounttable.mycluster.link./tmp</name>
             <value>hdfs://ns1/tmp</value>
       </property>
      <property>
          <name>fs.viewfs.mounttable.mycluster.link./projects/foo</name>
        <value>hdfs://ns2/projects/foo</value>
       </property>
     <property>
       <name>fs.viewfs.mounttable.mycluster.link./projects/bar</name>
       <value>hdfs://ns2/projects/bar</value>
      </property>
</configuration>

3.      hdfs-site.xml文件（使用ViewFs的话，相关的配置，上边的配置已经完成了，下面是一个两个高可用的集群联邦的配置）

<configuration>
        <property>
           <name>dfs.replication</name>
            <value>3</value>
          </property>
          <property>
            <name>dfs.namenode.name.dir</name>
           <value>/hadoop/dfs/name</value>
          </property>
          <property>
           <name>dfs.datanode.data.dir</name>
           <value>/hadoop/dfs/data/data1</value>
          </property>
                <!--
          <property>
            <name>dfs.namenode.secondary.http-address</name>
            <value>hadoopb.highgo.com:50090</value>
          </property>
           <property>
            <name>dfs.namenode.secondary.https-address</name>
             <value>hadoopb.highgo.com:50091</value>
           </property>
           -->
            <property>
              <name>dfs.nameservices</name>
              <value>ns1,ns2</value>
            </property>
             <property>
                  <name>dfs.ha.namenodes.ns1</name>
                 <value>nna,nnb</value>
             </property>
             <property>
                   <name>dfs.ha.namenodes.ns2</name>
                   <value>nng,nnh</value>
             </property>
             <property>
              <name>dfs.namenode.rpc-address.ns1.nna</name>
                <value>hadoopa.highgo.com:8020</value>
                 </property>
                 <property>
                  <name>dfs.namenode.rpc-address.ns1.nnb</name>
                     <value>hadoopb.highgo.com:8020</value>
                     </property>
        <property>
         <name>dfs.namenode.http-address.ns1.nna</name>
           <value>hadoopa.highgo.com:50070</value>
            </property>
            <property>
             <name>dfs.namenode.http-address.ns1.nnb</name>
               <value>hadoopb.highgo.com:50070</value>
                </property>
          <property>
           <name>dfs.namenode.shared.edits.dir.ns1</name>
              <value>qjournal://hadoopa.highgo.com:8485;hadoopb.highgo.com:8485;hadoopc.highgo.com:8485/ns1</value>
              </property>
         <property>
          <name>dfs.client.failover.proxy.provider.ns1</name>
             <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
             </property>
<property>
         <name>dfs.namenode.rpc-address.ns2.nng</name>
         <value>hadooph.highgo.com:8020</value>
</property>
<property>
         <name>dfs.namenode.rpc-address.ns2.nnh</name>
        <value>hadoopg.highgo.com:8020</value>
</property>
<property>
    <name>dfs.namenode.http-address.ns2.nng</name>
     <value>hadooph.highgo.com:50070</value>
</property>
<property>
         <name>dfs.namenode.http-address.ns2.nnh</name>
          <value>hadoopg.highgo.com:50070</value>
</property>
<!--
<property>
      <name>dfs.namenode.shared.edits.dir.ns2</name>
      <value>qjournal://hadoopf.highgo.com:8485;hadoopg.highgo.com:8485;hadooph.highgo.com:8485/ns2</value>
</property>-->
<property>                         
        <name>dfs.client.failover.proxy.provider.ns2</name>
       <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
</property>
        <property>
         <name>dfs.ha.fencing.methods</name>
            <value>sshfence</value>
            </property>
<property>
 <name>dfs.ha.fencing.ssh.private-key-files</name>
   <value>/home/hihadoop/.ssh/id_rsa</value>
    </property>
<property>
   <name>dfs.ha.automatic-failover.enabled.ns1</name>
      <value>true</value>
       </property>
<property>
  <name>dfs.ha.automatic-failover.enabled.ns2</name>
         <value>true</value>
                </property>
</configuration>

4.      格式化集群。需要在两个NameNode集群上分别格式化。启动整个JNs，在每一个集群上，在其中一个NameNode执行

hdfs namenode -format -clusterId mycluster

然后启动

hadoop-daemon.sh start namenode

在另一个NameNode上执行

hdfs namenode –bootstrapStandby

然后启动

hadoop-daemon.sh start namenode

在两个NameNode集群的任意NameNode上执行

hdfs zkfc –formatZK

在所有节点执行

hadoop-daemon.sh start zkfc

启动所有的DataNode

5.      此时可以用Hadoop shell进行一些操作了，操作的目录是所用的NameNode就是挂载表中的配置。