Docker中Hadoop集群搭建

使用腾讯云主机，docker构建集群测试环境。

环境

1、操作系统： CentOS 7.2 64位

网路设置

hostname	IP
cluster-master	172.18.0.2
cluster-slave1	172.18.0.3
cluster-slave2	172.18.0.4
cluster-slave3	172.18.0.5

Docker 安装

curl -sSL https://get.daocloud.io/docker | sh

##换源
###这里可以参考这篇文章http://www.jianshu.com/p/34d3b4568059
curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://67e93489.m.daocloud.io

##开启自启动
systemctl enable docker
systemctl start docker

拉去Centos镜像

docker pull daocloud.io/library/centos:latest

使用docker ps 查看下载的镜像

创建容器

按照集群的架构，创建容器时需要设置固定IP，所以先要在docker使用如下命令创建固定IP的子网

docker network create --subnet=172.18.0.0/16 netgroup

docker的子网创建完成之后就可以创建固定IP的容器了

#cluster-master
#-p 设置docker映射到容器的端口 后续查看web管理页面使用
docker run -d --privileged -ti -v /sys/fs/cgroup:/sys/fs/cgroup --name cluster-master -h cluster-master -p 18088:18088 -p 9870:9870 --net netgroup --ip 172.18.0.2 daocloud.io/library/centos /usr/sbin/init

#cluster-slaves
docker run -d --privileged -ti -v /sys/fs/cgroup:/sys/fs/cgroup --name cluster-slave1 -h cluster-slave1 --net netgroup --ip 172.18.0.3 daocloud.io/library/centos /usr/sbin/init

docker run -d --privileged -ti -v /sys/fs/cgroup:/sys/fs/cgroup --name cluster-slave2 -h cluster-slave2 --net netgroup --ip 172.18.0.4 daocloud.io/library/centos /usr/sbin/init

docker run -d --privileged -ti -v /sys/fs/cgroup:/sys/fs/cgroup --name cluster-slave3 -h cluster-slave3 --net netgroup --ip 172.18.0.5 daocloud.io/library/centos /usr/sbin/init

启动控制台并进入docker容器中：

docker exec -it cluster-master /bin/bash

安装OpenSSH免密登录

1、cluster-master安装：

#cluster-master需要修改配置文件（特殊）
#cluster-master

#安装openssh
[root@cluster-master /]# yum -y install openssh openssh-server openssh-clients

[root@cluster-master /]# systemctl start sshd
####ssh自动接受新的公钥
####master设置ssh登录自动添加kown_hosts
[root@cluster-master /]# vi /etc/ssh/ssh_config
#将原来的StrictHostKeyChecking ask
#设置StrictHostKeyChecking为no
#保存
[root@cluster-master /]# systemctl restart sshd

2、分别对slaves安装OpenSSH

#安装openssh
[root@cluster-slave1 /]#yum -y install openssh openssh-server openssh-clients

[root@cluster-slave1 /]# systemctl start sshd

3、cluster-master公钥分发

在master机上执行
ssh-keygen -t rsa
并一路回车，完成之后会生成~/.ssh目录，目录下有id_rsa（私钥文件）和id_rsa.pub（公钥文件），再将id_rsa.pub重定向到文件authorized_keys

ssh-keygen -t rsa
#一路回车

[root@cluster-master /]# cat ~/.ssh/id_rsa.pub > ~/.ssh/authorized_keys

文件生成之后用scp将公钥文件分发到集群slave主机

[root@cluster-master /]# ssh root@cluster-slave1 'mkdir ~/.ssh'
[root@cluster-master /]# scp ~/.ssh/authorized_keys root@cluster-slave1:~/.ssh
[root@cluster-master /]# ssh root@cluster-slave2 'mkdir ~/.ssh'
[root@cluster-master /]# scp ~/.ssh/authorized_keys root@cluster-slave2:~/.ssh
[root@cluster-master /]# ssh root@cluster-slave3 'mkdir ~/.ssh'
[root@cluster-master /]# scp ~/.ssh/authorized_keys root@cluster-slave3:~/.ssh

分发完成之后测试(ssh root@cluster-slave1)是否已经可以免输入密码登录

Ansible安装

[root@cluster-master /]# yum -y install epel-release
[root@cluster-master /]# yum -y install ansible
#这样的话ansible会被安装到/etc/ansible目录下

此时我们再去编辑ansible的hosts文件

vi /etc/ansible/hosts

[cluster]
cluster-master
cluster-slave1
cluster-slave2
cluster-slave3

[master]
cluster-master

[slaves]
cluster-slave1
cluster-slave2
cluster-slave3

配置docker容器hosts

由于/etc/hosts文件在容器启动时被重写，直接修改内容在容器重启后不能保留，为了让容器在重启之后获取集群hosts，使用了一种启动容器后重写hosts的方法。
需要在~/.bashrc中追加以下指令

:>/etc/hosts
cat >>/etc/hosts<<EOF
127.0.0.1   localhost
172.18.0.2  cluster-master
172.18.0.3  cluster-slave1
172.18.0.4  cluster-slave2
172.18.0.5  cluster-slave3
EOF

source ~/.bashrc

使配置文件生效,可以看到/etc/hosts文件已经被改为需要的内容

[root@cluster-master ansible]# cat /etc/hosts
127.0.0.1   localhost
172.18.0.2  cluster-master
172.18.0.3  cluster-slave1
172.18.0.4  cluster-slave2
172.18.0.5  cluster-slave3

用ansible分发.bashrc至集群slave下

ansible cluster -m copy -a "src=~/.bashrc dest=~/"

软件环境配置

下载JDK1.8并解压缩至/opt 目录下

下载hadoop3 到/opt目录下，解压安装包，并创建链接文件

tar -xzvf hadoop-3.2.0.tar.gz
ln -s hadoop-3.2.0 hadoop

配置java和hadoop环境变量

编辑 ~/.bashrc文件

# hadoop
export HADOOP_HOME=/opt/hadoop-3.2.0
export PATH=$HADOOP_HOME/bin:$HADOOP_HOME/sbin:$PATH

#java
export JAVA_HOME=/opt/jdk8
export PATH=$HADOOP_HOME/bin:$PATH

使文件生效：

source .bashrc

配置hadoop运行所需配置文件

cd $HADOOP_HOME/etc/hadoop/

1、修改core-site.xml

<configuration>
    <property>
        <name>hadoop.tmp.dir</name>
        <value>/home/hadoop/tmp</value>
        <description>A base for other temporary directories.</description>
    </property>
    <!-- file system properties -->
    <property>
        <name>fs.default.name</name>
        <value>hdfs://cluster-master:9000</value>
    </property>
    <property>
    <name>fs.trash.interval</name>
        <value>4320</value>
    </property>
</configuration>

2、修改hdfs-site.xml

<configuration>
<property>
   <name>dfs.namenode.name.dir</name>
   <value>/home/hadoop/tmp/dfs/name</value>
 </property>
 <property>
   <name>dfs.datanode.data.dir</name>
   <value>/home/hadoop/data</value>
 </property>
 <property>
   <name>dfs.replication</name>
   <value>3</value>
 </property>
 <property>
   <name>dfs.webhdfs.enabled</name>
   <value>true</value>
 </property>
 <property>
   <name>dfs.permissions.superusergroup</name>
   <value>staff</value>
 </property>
 <property>
   <name>dfs.permissions.enabled</name>
   <value>false</value>
 </property>
 </configuration>

3、修改mapred-site.xml

<configuration>
<property>
  <name>mapreduce.framework.name</name>
  <value>yarn</value>
</property>
<property>
    <name>mapred.job.tracker</name>
    <value>cluster-master:9001</value>
</property>
<property>
  <name>mapreduce.jobtracker.http.address</name>
  <value>cluster-master:50030</value>
</property>
<property>
  <name>mapreduce.jobhisotry.address</name>
  <value>cluster-master:10020</value>
</property>
<property>
  <name>mapreduce.jobhistory.webapp.address</name>
  <value>cluster-master:19888</value>
</property>
<property>
  <name>mapreduce.jobhistory.done-dir</name>
  <value>/jobhistory/done</value>
</property>
<property>
  <name>mapreduce.intermediate-done-dir</name>
  <value>/jobhisotry/done_intermediate</value>
</property>
<property>
  <name>mapreduce.job.ubertask.enable</name>
  <value>true</value>
</property>
</configuration>

4、yarn-site.xml

<configuration>
    <property>
   <name>yarn.resourcemanager.hostname</name>
   <value>cluster-master</value>
 </property>
 <property>
   <name>yarn.nodemanager.aux-services</name>
   <value>mapreduce_shuffle</value>
 </property>
 <property>
   <name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
   <value>org.apache.hadoop.mapred.ShuffleHandler</value>
 </property>
 <property>
   <name>yarn.resourcemanager.address</name>
   <value>cluster-master:18040</value>
 </property>
<property>
   <name>yarn.resourcemanager.scheduler.address</name>
   <value>cluster-master:18030</value>
 </property>
 <property>
   <name>yarn.resourcemanager.resource-tracker.address</name>
   <value>cluster-master:18025</value>
 </property> <property>
   <name>yarn.resourcemanager.admin.address</name>
   <value>cluster-master:18141</value>
 </property>
<property>
   <name>yarn.resourcemanager.webapp.address</name>
   <value>cluster-master:18088</value>
 </property>
<property>
   <name>yarn.log-aggregation-enable</name>
   <value>true</value>
 </property>
<property>
   <name>yarn.log-aggregation.retain-seconds</name>
   <value>86400</value>
 </property>
<property>
   <name>yarn.log-aggregation.retain-check-interval-seconds</name>
   <value>86400</value>
 </property>
<property>
   <name>yarn.nodemanager.remote-app-log-dir</name>
   <value>/tmp/logs</value>
 </property>
<property>
   <name>yarn.nodemanager.remote-app-log-dir-suffix</name>
   <value>logs</value>
 </property>
</configuration>

打包hadoop 向slaves分发

tar -cvf hadoop-dis.tar hadoop hadoop-3.2.0

使用ansible-playbook分发.bashrc和hadoop-dis.tar至slave主机

---
- hosts: cluster
  tasks:
    - name: copy .bashrc to slaves
      copy: src=~/.bashrc dest=~/
      notify:
        - exec source
    - name: copy hadoop-dis.tar to slaves
      unarchive: src=/opt/hadoop-dis.tar dest=/opt

  handlers:
    - name: exec source
      shell: source ~/.bashrc

将以上yaml保存为hadoop-dis.yaml，并执行

ansible-playbook hadoop-dis.yaml

hadoop-dis.tar会自动解压到slave主机的/opt目录下

Hadoop 启动

格式化namenode

hadoop namenode -format

如果看到storage format success等字样，即可格式化成功

启动集群

cd $HADOOP_HOME/sbin
start-all.sh

启动后可使用jps命令查看是否启动成功

注意：
在实践中遇到节点slaves 上的datanode服务没有启动，查看slave上目录结构发现
没有生成配置文件中设置的文件夹，比如：core-site.xml中

<property>
        <name>hadoop.tmp.dir</name>
        <value>/home/hadoop/tmp</value>
        <description>A base for other temporary directories.</description>
    </property>

hdfs-site.xml文件中:

<property>
   <name>dfs.namenode.name.dir</name>
   <value>/home/hadoop/tmp/dfs/name</value>
 </property>
 <property>
   <name>dfs.datanode.data.dir</name>
   <value>/home/hadoop/data</value>
 </property>

手动到节点中生成这些文件夹，之后删除master中这些文件夹和$HADOOP_HOME下的logs文件夹,之后重新格式化namenode