前置步骤:

1). 第一阶段：Hadoop单机伪分布(single)

2). 第二阶段：Hadoop完全分布式(full)

第三阶段: Hadoop高可用(HA)

0. 步骤概述

1). 为完全分布式保存hadoop配置

2). 为hadoop2配置hadoop1的ssh免密

3). 在hadoop2上配置zookeeper

4). 在hadoop1上修改hadoop配置文件为HA高可用模式

5). 第一次启动HA

6). 常规启动HA

7). 在完全分布式集群上测试wordcount程序

1. 为完全分布式保存hadoop配置

1.1 进入$HADOOP_HOME/etc/目录

[root@hadoop1 ~]# cd /opt/test/hadoop-2.6.5/etc

1.2 备份hadoop完全分布式配置,命名为hadoop-full，供以后使用

[root@hadoop1 etc]# cp -r hadoop/ hadoop-full

1.3 查看$HADOOP_HOME/etc/目录，备份成功

[root@hadoop1 etc]# ls
hadoop hadoop-full

# hadoop-full保留了已有配置，接下来高可用的配置继续在hadoop文件夹内修改

2. 为hadoop2配置hadoop1的ssh免密

2.1 在hadoop2上生成密匙

[root@hadoop2 ~]# ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa

2.2 在hadoop2上配置对自身免密

[root@hadoop2 ~]# cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

2.3 在hadoop2上查看authorized_keys密匙

[root@hadoop2 ~]# cat ~/.ssh/authorized_keys
ssh-dss ***** root@hadoop1
ssh-dss ***** root@hadoop2

# hadoop2上的authorized_keys现在有两个，一个来自hadoop1，一个是自身的

2.4 在hadoop2上将公匙拷贝给hadoop1

2.4.1 方式一：直接用ssh-copy-id –i命令从hadoop2上拷贝到hadoop1
[root@hadoop2 ~]# ssh-copy-id -i ~/.ssh/id_dsa.pub hadoop1

2.4.2.1 方式二(1)：首先在hadoop2上操作，用scp命令将公匙复制到hadoop1
[root@hadoop2 ~]# scp ~/.ssh/id_dsa.pub hadoop1:~/.ssh/hadoop2.pub

2.4.2.2 方式二(2)：接着在hadoop1上使用cat命令使hadoop2公匙生效
[root@hadoop2 ~]# cat hadoop2.pub >> authorized_keys

2.5 在hadoop2上测试ssh到hadoop1是否成功免密

[root@hadoop2 ~]# ssh hadoop1
[root@hadoop1 ~]# 

#成功进入hadoop1，没有提示输入密码，表示免密成功

3. 在hadoop2上配置zookeeper

3.1 进入/opt/test/目录

[root@hadoop2 ~]# cd /opt/test
[root@hadoop2 test]

3.2 通过xftp将zookeeper-3.4.6.tar.gz上传到hadoop2的/opt/test/目录

3.3 解压缩文件

[root@hadoop2 test]# tar -zxvf zookeeper-3.4.6.tar.gz

3.4 为hadoop2,hadoop3,hadoop4设置zookeeper环境变量

3.4.1 在hadoop2上编辑/etc/profile,增加zookeeper环境变量配置
[root@hadoop2 ~]# vim /etc/profile
export ZOOKEEPER_PREFIX=/opt/test/zookeeper-3.4.6
export PATH=$PATH:$JAVA_HOME/bin:$HADOOP_PREFIX/bin:$HADOOP_PREFIX/sbin:$ZOOKEEPER_PREFIX/bin

3.4.2 分发hadoop2上的/etc/profile到hadoop3,hadoop4
[root@hadoop2 ~]# scp /etc/profile hadoop2:/etc/
[root@hadoop2 ~]# scp /etc/profile hadoop2:/etc/

3.4.3 在hadoop2,hadoop3,hadoop4上使/etc/profile生效
[root@hadoop2 ~]# source /etc/profile
[root@hadoop3 ~]# source /etc/profile
[root@hadoop4 ~]# source /etc/profile

3.5 编辑zoo.cfg文件

3.5.0 进入/opt/etc/zookeeper-3.4.6/conf目录
[root@hadoop2 ~]# cd /opt/test/zookeeper-3.4.6/conf
[root@hadoop2 conf]

3.5.1将zoo_sample.cfg复制为zoo.cfg文件
[root@hadoop2 conf]# cp zoo_sample.cfg zoo.cfg

3.5.2 在zoo.cfg中添加如下内容
[root@hadoop2 conf]# vim zoo.cfg
# 配置zookeeper数据存放目录
dataDir=/var/test/zk/
# 设置zookeeper位置信息
server.1=hadoop2:2888:3888
server.2=hadoop3:2888:3888
server.3=hadoop4:2888:3888

3.6 设置zookeeper节点对应的ID

3.6.1 在hadoop2上进入/var/test/
[root@hadoop2 ~]# cd /var/test/

3.6.2 在test目录下创建zk目录
[root@hadoop2 test]# mkdir zk

3.6.3 进入/var/test/zk目录
[root@hadoop2 test]# cd /var/test/zk

3.6.4 在/var/test/zk目录下生成myid文件
[root@hadoop2 zk]# echo 1 > myid

3.6.5 分别在hadoop3和hadoop4重复3.6.1~3.6.4的操作，其中3.6.4步骤中hadoop3的myid内容为2，hadoop4的myid内容为3

3.6.6 查看hadoop2,hadoop3,hadoop4的myid文件
[root@hadoop2 zk]# cat myid
1

[root@hadoop3 zk]# cat myid
2

[root@hadoop4 zk]# cat myid
3

3.7 将zookeeper-3.4.6目录分发到其他节点上

3.7.1 在hadoop2上进入/opt/test/目录
[root@hadoop2 zk]# cd /opt/test/

3.7.2 分发zookeeper-3.4.6目录到hadoop3,hadoop4
[root@hadoop2 test]# scp -r zookeeper-3.4.6 hadoop3:`pwd`
[root@hadoop2 test]# scp -r zookeeper-3.4.6 hadoop4:`pwd`

3.8 验证zookeeper是否安装成功

3.8.1 在hadoop2,hadoop3,hadoop4上分别启动zookeeper
[root@hadoop2 test]# zkServer.sh start
[root@hadoop3 test]# zkServer.sh start
[root@hadoop4 test]# zkServer.sh start

3.8.2 查看zookeeper状态
# 如果成功，可以看到2个follower，1个leader，leader由选举产生
[root@hadoop2 test]# zkServer.sh status
JMX enabled by default
Using config: /opt/test/zookeeper-3.4.6/bin/../conf/zoo.cfg
Mode: follower

[root@hadoop3 test]# zkServer.sh status
JMX enabled by default
Using config: /opt/test/zookeeper-3.4.6/bin/../conf/zoo.cfg
Mode: follower

[root@hadoop4 test]# zkServer.sh status
JMX enabled by default
Using config: /opt/test/zookeeper-3.4.6/bin/../conf/zoo.cfg
Mode: leader

3.9 使用zookeeper客户端

3.9.1 进入zookeeper客户端
[root@hadoop2 test]# zkCli.sh
[zk: localhost:2181(CONNECTED) 0]
显示上述信息表示进入成功

3.9.2 退出zookeeper客户端
[zk: localhost:2181(CONNECTED) 0] quit
Quitting...
2017-11-30 20:43:17,953 [myid:] - INFO  [main:ZooKeeper@684] - Session: ** closed
2017-11-30 20:43:17,953 [myid:] – INFO [main-EventThread:ClientCnxn$EventThread@512] - EventThread shut down

3.9.3 停止zookeeper服务
[root@hadoop4 test]# zkServer.sh stop
JMX enabled by default
Using config: /opt/test/zookeeper-3.4.6/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED

4. 在hadoop1上修改hadoop配置文件为HA高可用模式

4.1 进入$HADOOP_HOME/etc/hadoop目录

[root@hadoop1 ~]# cd /opt/test/hadoop-2.6.5/etc/hadoop/

4.2 修改hdfs-site.xml文件

[root@hadoop1 hadoop]# vim hdfs-site.xml

4.2.1删除secondary的配置信息
<property>
   <name>dfs.namenode.secondary.http-address</name>
   <value>hadoop2:50090</value>
</property>

4.2.2 将原有hdfs-site.xml配置替换为如下内容
<configuration>
<property>
   <name>dfs.replication</name>
   <value>3</value>
</property>
<!--定义nameservices逻辑名称-->
<property>
  <name>dfs.nameservices</name>
  <value>mycluster</value>
</property>
<!--映射nameservices逻辑名称到namenode逻辑名称-->
<property>
  <name>dfs.ha.namenodes.mycluster</name>
  <value>nn1,nn2</value>
</property>
<!--映射namenode逻辑名称到真实主机名称(RPC)-->
<property>
  <name>dfs.namenode.rpc-address.mycluster.nn1</name>
  <value>hadoop1:8020</value>
</property>
<!--映射namenode逻辑名称到真实主机名称(RPC)-->
<property>
  <name>dfs.namenode.rpc-address.mycluster.nn2</name>
  <value>hadoop2:8020</value>
</property>
<!--映射namenode逻辑名称到真实主机名称(HTTP)-->
<property>
  <name>dfs.namenode.http-address.mycluster.nn1</name>
  <value>hadoop1:50070</value>
</property>
<!--映射namenode逻辑名称到真实主机名称(HTTP)-->
<property>
  <name>dfs.namenode.http-address.mycluster.nn2</name>
  <value>hadoop2:50070</value>
</property>
<!--配置journalnode集群位置信息及目录-->
<property>
  <name>dfs.namenode.shared.edits.dir</name>
<value>qjournal://hadoop1:8485;hadoop2:8485;hadoop3:8485/mycluster</value>
</property>
<property>
  <name>dfs.journalnode.edits.dir</name>
  <value>/var/test/hadoop/ha/jn</value>
</property>
<!--配置故障切换实现类-->
<property>
  <name>dfs.client.failover.proxy.provider.mycluster</name>
<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
</property>
<!--指定切换方式为SSH免密钥方式-->
<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_dsa</value>
</property>
<!--设置自动切换-->
<property>
   <name>dfs.ha.automatic-failover.enabled.mycluster</name>
   <value>true</value>
</property>
</configuration>

4.3 修改core-site.xml文件，将原有配置替换如下

[root@hadoop1 hadoop]# vim core-site.xml

<configuration>
<!--设置fs.defaultFS为nameservices的逻辑主机名-->
    <property>
        <name>fs.defaultFS</name>
        <value>hdfs://mycluster</value>
</property>
<!--设置zookeeper数据存放目录-->
    <property>
        <name>hadoop.tmp.dir</name>
        <value>/var/test/hadoop/ha</value>
</property>
<!--设置zookeeper位置信息-->
<property>
        <name>ha.zookeeper.quorum.mycluster</name>
        <value>hadoop2:2181,hadoop3:2181,hadoop4:2181</value>
    </property>
</configuration>

4.4 将修改后的hdfs-site.xml和core-site.xml分发到其他节点

[root@hadoop1 hadoop]# scp hdfs-site.xml core-site.xml hadoop2:`pwd`
[root@hadoop1 hadoop]# scp hdfs-site.xml core-site.xml hadoop3:`pwd`
[root@hadoop1 hadoop]# scp hdfs-site.xml core-site.xml hadoop4:`pwd`

5. 第一次启动HA

5.1 启动zookeeper

5.1.1 在hadoop2,hadoop3,hadoop4上分别启动zookeeper
[root@hadoop2 ~]# zkServer.sh start
[root@hadoop3 ~]# zkServer.sh start
[root@hadoop4 ~]# zkServer.sh start

5.1.2 hadoop2,hadoop3,hadoop4进程显示如下
[root@hadoop2 ~]# jps
**** Jps
**** QuorumPeerMain

[root@hadoop3 ~]# jps
**** Jps
**** QuorumPeerMain

[root@hadoop4 ~]# jps
**** Jps
**** QuorumPeerMain

5.2 启动journalnode

5.2.1 在hadoop1,hadoop2,hadoop3上启动journalnode
[root@hadoop1 ~]# hadoop-daemon.sh start journalnode
[root@hadoop2 ~]# hadoop-daemon.sh start journalnode
[root@hadoop3 ~]# hadoop-daemon.sh start journalnode

5.2.2 hadoop1,hadoop2,hadoop3进程显示如下
[root@hadoop1 ~]# jps
**** Jps
**** JournalNode

[root@hadoop2 ~]# jps
**** Jps
**** QuorumPeerMain
**** JournalNode

[root@hadoop3 ~]# jps
**** Jps
**** QuorumPeerMain
**** JournalNode

5.3 在hadoop1上格式化namenode

[root@hadoop1 ~]# hdfs namenode -format

17/11/30 21:16:35 INFO namenode.NameNode: STARTUP_MSG: 
/************************************************************
……
SHUTDOWN_MSG: Shutting down NameNode at hadoop1/192.168.111.211
************************************************************/

5.4 在hadoop1上启动namenode

5.4.1 格式化完成后在hadoop1上启动namenode
[root@hadoop1 ~]# hadoop-daemon.sh start namenode
starting namenode, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-namenode-hadoop1.out

5.4.2 hadoop1进程显示如下
[root@hadoop1 ~]# jps
**** Jps
**** JournalNode
**** NameNode

5.5 在hadoop2，即另一台namenode上同步hadoop1的CID等信息

[root@hadoop2 ~]# hdfs namenode -bootstrapStandby
17/11/30 21:20:27 INFO namenode.NameNode: STARTUP_MSG: 
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at hadoop2/192.168.111.212
************************************************************/

5.6 在hadoop1上启动其他服务

[root@hadoop1 ~]# start-dfs.sh

17/11/30 21:21:17 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [hadoop1 hadoop2]
hadoop1: namenode running as process 1555. Stop it first.
hadoop2: starting namenode, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-namenode-hadoop2.out
hadoop2: starting datanode, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-datanode-hadoop2.out
hadoop3: starting datanode, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-datanode-hadoop3.out
hadoop4: starting datanode, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-datanode-hadoop4.out
Starting journal nodes [hadoop1 hadoop2 hadoop3]
hadoop1: journalnode running as process 1397. Stop it first.
hadoop3: journalnode running as process 1437. Stop it first.
hadoop2: journalnode running as process 1435. Stop it first.
17/11/30 21:21:31 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting ZK Failover Controllers on NN hosts [hadoop1 hadoop2]
hadoop1: starting zkfc, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-zkfc-hadoop1.out
hadoop2: starting zkfc, logging to /opt/test/hadoop-2.6.5/logs/hadoop-root-zkfc-hadoop2.out

5.7 在hadoop1上格式化zookeeper

[root@hadoop1 ~]# hdfs zkfc -formatZK
……
17/11/30 21:23:10 INFO ha.ActiveStandbyElector: Successfully created /hadoop-ha/mycluster in ZK.
17/11/30 21:23:10 INFO ha.ActiveStandbyElector: Session connected.
17/11/30 21:23:10 INFO zookeeper.ClientCnxn: EventThread shut down
17/11/30 21:23:10 INFO zookeeper.ZooKeeper: Session: 0x2600d0c1b960000 closed

5.8 在hadoop2,hadoop3,hadoop4上使用zkCli.sh查看格式化结果

5.8.1 进入zookeeper客户端
[root@hadoop2 ~]# zkCli.sh
[zk: localhost:2181(CONNECTED) 0]

5.8.2 使用ls /命令查看根目录
[zk: localhost:2181(CONNECTED) 0] ls /
[hadoop-ha, zookeeper]
#每个根目录都生成了hadoop-ha目录

*格式化namenode后出现datanode无法启动的情况，查看BUGFIX1

6. 常规启动HA

6.1 启动zookeeper

6.1.1 在hadoop2,hadoop3,hadoop4上分别启动zookeeper
[root@hadoop2 ~]# zkServer.sh start
[root@hadoop3 ~]# zkServer.sh start
[root@hadoop4 ~]# zkServer.sh start

6.1.2 hadoop2,hadoop3,hadoop4进程显示如下
[root@hadoop2 ~]# jps
**** Jps
**** QuorumPeerMain

[root@hadoop3 ~]# jps
**** Jps
**** QuorumPeerMain

[root@hadoop4 ~]# jps
**** Jps
**** QuorumPeerMain

6.2 启动hdfs集群

6.2.1 在hadoop1上启动整个集群start-dfs.sh
[root@hadoop1 ~]# start-dfs.sh

6.2.2 hadoop会启动如下进程：
hadoop1, hadoop2: namenode
hadoop2, hadoop3, hadoop4: datanode
hadoop1, hadoop2, hadoop3: journalnode
hadoop1, hadoop2: ZKFC

6.2.3 启动完成后各节点进程显示如下：
[root@hadoop1 ~]# jps
2559 JournalNode
2724 DFSZKFailoverController
2790 Jps
2366 NameNode

[root@hadoop2 ~]# jps
2099 JournalNode
2217 DFSZKFailoverController
2265 Jps
1754 QuorumPeerMain
2014 DataNode
1945 NameNode

[root@hadoop3 ~]# jps
1583 QuorumPeerMain
1714 DataNode
1799 JournalNode
1859 Jps

[root@hadoop4 ~]# jps
1685 Jps
1510 QuorumPeerMain
1613 DataNode

6.3 启动yarn

6.3.1 在hadoop1上启动yarn
[root@hadoop1 ~]# start-yarn.sh

6.3.2 启动完成后各集群进程如下
[root@hadoop1 ~]# jps
2559 JournalNode
2935 ResourceManager
2724 DFSZKFailoverController
3350 Jps
2366 NameNode

[root@hadoop2 ~]# jps
2099 JournalNode
2217 DFSZKFailoverController
1754 QuorumPeerMain
2381 NodeManager
2014 DataNode
2587 Jps
1945 NameNode

[root@hadoop3 ~]# jps
1583 QuorumPeerMain
1714 DataNode
2628 Jps
1901 NodeManager
1799 JournalNode

[root@hadoop4 ~]# jps
1728 NodeManager
1510 QuorumPeerMain
1613 DataNode
1891 Jps

7. 在完全分布式集群上测试wordcount程序

7.1 从hadoop1进入$HADOOP_HOME/share/hadoop/mapreduce/目录

[root@hadoop1 ~]# cd /opt/test/hadoop-2.6.5/share/hadoop/mapreduce/

7.2上传test.txt文件到根目录

7.2.1 默认上传
[root@hadoop1 mapreduce]# hadoop fs -put test.txt /

7.2.2 也可以指定blocksize
[root@hadoop1 mapreduce]# hdfs dfs -D dfs.blocksize=1048576 -put test.txt /

7.3 运行wordcount测试程序，输出到/output

[root@hadoop1 mapreduce]# 
hadoop jar hadoop-mapreduce-examples-2.6.5.jar wordcount /test.txt /output

#运行时会首先看到如下信息
INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032

7.4 查看mapreduce运行结果

[root@hadoop1 mapreduce]# hadoop dfs -text /output/part-*
hello    100003
world    200002
“hello    100000

后续步骤:

4). 第四阶段：Hadoop高可用+联邦+视图文件系统(HA+Federation+ViewFs)