Ubuntu16.04搭建HA集群hadoop-2.7.4

搭建高可用的Hadoop集群主要是两个配置文件:1.hdfs-site.xml 2.core-site.xml,这里我有五台机器：
node1:192.168.0.172,node2:192.168.0.104,node3:192.168.0.177,node4:192.168.0.158,node5:192.168.0.136
其中zookeeper在五台机器上都有，node1与node2是两台namenode,其余三台是datanode和journalnode
1.首先把/etc/hosts文件改好：
127.0.0.1 localhost localhost4 localhost4.localdomain4
::1 localhost localhost6 localhost6.localdomain6
192.168.0.172 node1
192.168.0.104 node2
192.168.0.177 node3
192.168.0.158 node4
192.168.0.136 node52.配置/etc/profile的环境变量：
export JAVA_HOME=/opt/jdk
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

export HADOOP_HOME=/opt/hadoop-2.7.4
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin
export HADOOP_CONF_DIR=$HADOOP_HOME/etc/hadoop
export YARN_CONF_DIR=$HADOOP_HOME/etc/hadoop3.修改 etc/hadoop/hadoop-env.sh文件：

export JAVA_HOME=/opt/hadoop-2.7.4

4.设置免密码登录，这里主要是把node1和node2的公钥给加到其他的机器上边:

ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

注意：这个命令要在/root下运行
5.下面是最重要的两个配置文件(hdfs-site.xml和core-site.xml):1)hdfs-site.xml<configuration>
<property>
<name>dfs.nameservices</name>
<value>mycluster</value>
</property>
<property>
<name>dfs.ha.namenodes.mycluster</name>
<value>nn1,nn2</value>
</property>
<property>
<name>dfs.namenode.rpc-address.mycluster.nn1</name>
<value>node1:8020</value>
</property>
<property>
<name>dfs.namenode.rpc-address.mycluster.nn2</name>
<value>node2:8020</value>
</property>
<property>
<name>dfs.namenode.http-address.mycluster.nn1</name>
<value>node1:50070</value>
</property>
<property>
<name>dfs.namenode.http-address.mycluster.nn2</name>
<value>node2:50070</value>
</property>
<property>
<name>dfs.namenode.shared.edits.dir</name>
<value>qjournal://node3:8485;node4:8485;node5:8485/mycluster</value>
</property>
<property>
<name>dfs.client.failover.proxy.provider.mycluster</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>/root/.ssh/id_rsa</value>
</property>
<property>
<name>dfs.journalnode.edits.dir</name>
<value>/opt/to/journal/node/local/data</value>
</property>
<property>
<name>dfs.ha.automatic-failover.enabled</name>
<value>true</value>
</property>
</configuration>2)core-site.xml

<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://mycluster</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/opt/hadoop-2.7.4/tmp</value>
</property>
<property>
<name>ha.zookeeper.quorum</name>
<value>node1:2181,node2:2181,node3:2181,node4:2181,node5:2181</value>
</property>
</configuration>

修改slaves文件，把node3，node4，node5加进去，也就是把datanode的信息加到文件里边
6.配置zookeeper-3.6.4:# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/opt/zoo
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance #
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
server.1=node1:2888:3888
server.2=node2:2888:3888
server.3=node3:2888:3888
server.4=node4:2888:3888
server.5=node5:2888:3888注意：其余的不用怎么改就是加上最后面这一段就好了，然后在dataDir的路径下新建一个myid文件，把自己的代号（也就是server.x中的x）写到文件里边,最后到bin里边运行./zkServer.sh start,注意看下log文件是不是启动成功！7.启动journalnode（node3-node5）:hadoop-daemon.sh start journalnode8.格式化zookeeper：hdfs zkfc -formatZK9.最后format一下namenode：

hdfs namenode -format

 10.在没有格式化的namenode上执行：hdfs namenode -bootstrapStandby将format后在tmp中生成的文件复制到另外一台namenode上，然后启动start-dfs.sh，这样一个HA基本上是搭建好了
11.如果发现某一台机器少了个节点什么的可以用下面这个命令：
hadoop-daemon.sh start namenode/datanode
注意：如果zkfc的日志文件出现了如下的错误 在zkfc的日志里面，有一个warn：PATH=$PATH:/sbin:/usr/sbin fuser -v -k -n tcp 8090 via ssh: bash: fuser: 未找到命令，这样就可以了，一个高可用的集群就这样搭好了
yum install psmisc