在 《Docker中搭建Hadoop-2.6单机伪分布式集群》中在容器中操作来搭建伪分布式的Hadoop集群，这一节中将主要通过Dokcerfile 来完成这项工作。
1 获取一个简单的Docker系统镜像,并建立一个容器。
这里我选择下载CentOS镜像
docker pull centos
通过docker tag命令将下载的CentOS镜像名称换成centos，并删除老标签
docker tag docker.io/centos centos
docker rmr docker.io/centos
2. JDK的安装和配置
去Oracle官网提前下载好所需的jdk。
建立文件夹，并将jdk copy到文件夹下
[root@centos-docker ~]# mkdir centos-jdk [root@centos-docker ~]# mv jdk-7u79-linux-x64.tar.gz ./centos-jdk/ [root@centos-docker ~]# cd centos-jdk/ [root@centos-docker centos-jdk]# ls jdk-7u79-linux-x64.tar.gz
在centos-jdk文件夹中建立Dockerfile，其内容如下：
# CentOS with JDK 7 # Author amei # build a new image with basic centos FROM centos # who is the author MAINTAINER amei # make a new directory to store the jdk files RUN mkdir /usr/local/java # copy the jdk archive to the image,and it will automaticlly unzip the tar file ADD jdk-7u79-linux-x64.tar.gz /usr/local/java/ # make a symbol link RUN ln -s /usr/local/java/jdk1.7.0_79 /usr/local/java/jdk # set environment variables ENV JAVA_HOME /usr/local/java/jdk ENV JRE_HOME ${JAVA_HOME}/jre ENV CLASSPATH .:${JAVA_HOME}/lib:${JRE_HOME}/lib ENV PATH ${JAVA_HOME}/bin:$PATH
根据Dokcerfile创建新镜像：
# 注意后边的 . 不能忘了
[root@centos-docker centos-jdk]# docker build -t="centos-jdk" . Sending build context to Docker daemon 153.5 MB Step 1 : FROM centos ---> e8f1bdb3b6a7 ..................................... Step 9 : ENV PATH ${JAVA_HOME}/bin:$PATH ---> Running in 5ecbe2fac774 ---> ad1110b84433 Removing intermediate container 5ecbe2fac774 Successfully built ad1110b84433
查看新建立的镜像
[root@centos-docker centos-jdk]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE centos-jdk latest ad1110b84433 5 minutes ago 503 MB centos latest e8f1bdb3b6a7 2 weeks ago 196.7 MB
建立容器，查看新的镜像中的JDK是否正确
[root@centos-docker centos-jdk]# docker run -it centos-jdk /bin/bash [root@b665dbff9965 /]# java -version # 出来结果表明配置没问题 java version "1.7.0_79" Java(TM) SE Runtime Environment (build 1.7.0_79-b15) Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode) [root@b665dbff9965 /]# echo $JAVA_HOME /usr/local/java/jdk
3. 在前一步基础上安装ssh
建立新的文件夹，并在其下建立Dokcerfile文件，其内容为：
# build a new image with centos-jdk
FROM centos-jdk
# who is the author
MAINTAINER amei
# install openssh
RUN yum -y install openssh-server openssh-clients
#generate key files
RUN ssh-keygen -q -t rsa -b 2048 -f /etc/ssh/ssh_host_rsa_key -N ''
RUN ssh-keygen -q -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key -N ''
RUN ssh-keygen -q -t dsa -f /etc/ssh/ssh_host_ed25519_key -N ''
# login localhost without password
RUN ssh-keygen -f /root/.ssh/id_rsa -N ''
RUN touch /root/.ssh/authorized_keys
RUN cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys
# set password of root
RUN echo "root:1234" | chpasswd
# open the port 22
EXPOSE 22
# when start a container it will be executed
CMD ["/usr/sbin/sshd","-D"]
利用此Dockerfile 建立镜像：
[root@centos-docker centos-jdk-ssh]# docker build -t "centos-jdk-ssh" . Sending build context to Docker daemon 2.56 kB Step 1 : FROM centos-jdk ---> ad1110b84433 。。。。。。。。。。。。。。。。。。。。。。。。 Successfully built 5286623a6cc0
验证建立好的镜像：
#在刚才的镜像之上建立容器
[root@centos-docker centos-jdk-ssh]# docker run -it centos-jdk-ssh /bin/bash [root@118f3d29fc73 /]# /usr/sbin/sshd #开启sshd服务 [root@118f3d29fc73 /]# ssh root@localhost #登陆到本机 The authenticity of host 'localhost (::1)' can't be established. # 观察确实不用密码即可登陆 ECDSA key fingerprint is b7:f0:33:15:c9:ca:12:8b:93:0d:45:95:6f:43:4f:78. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts. [root@118f3d29fc73 ~]# exit #退出容器 logout Connection to localhost closed.
4. 安装Hdoop2.6
首先先下载好hadoop安装包。
建立文件夹，并在文件夹下建立如下几个文件。
编辑core-site.xml文件
<?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?> <configuration> <property> <name>hadoop.tmp.dir</name> <value>file:/data/hadoop/tmp</value> </property> <property> <name>fs.defaultFS</name> <value>hdfs://localhost:9000</value> </property> </configuration>
编辑hdfs-site.xml文件
<?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?> <configuration> <property> <name>dfs.replication</name> <value>1</value> </property> <property> <name>dfs.namenode.name.dir</name> <value>file:/data/hadoop/dfs/name</value> </property> <property> <name>dfs.datanode.data.dir</name> <value>file:/data/hadoop/dfs/data</value> </property> </configuration>
在其下建立Dokcerfile文件，其内容为：
# build a new image with centos-jdk-ssh
FROM centos-jdk-ssh
# who is the author
MAINTAINER amei
# install some important software
RUN yum -y install net-tools which
# copy the hadoop archive to the image,and it will automaticlly unzip the tar file
ADD hadoop-2.6.0.tar.gz /usr/local/
# make a symbol link
RUN ln -s /usr/local/hadoop-2.6.0 /usr/local/hadoop
# copy the configuration file to image
COPY core-site.xml /usr/local/hadoop/etc/hadoop/
COPY hdfs-site.xml /usr/local/hadoop/etc/hadoop/
# change hadoop environment variables
RUN sed -i "s?JAVA_HOME=${JAVA_HOME}?JAVA_HOME=/usr/local/java/jdk?g" /usr/local/hadoop/etc/hadoop/hadoop-env.sh
# set environment variables
ENV HADOOP_HOME /usr/local/hadoop
ENV PATH ${HADOOP_HOME}/bin:${HADOOP_HOME}/sbin:$PATH
此时文件夹下的文件有：
[root@centos-docker centos-hadoop]# ll
total 190704
-rw-r--r--. 1 root root 403 Aug 7 06:52 core-site.xml
-rw-r--r--. 1 root root 708 Aug 7 06:52 Dockerfile
-rwxr-x---. 1 root root 195257604 Aug 7 04:44 hadoop-2.6.0.tar.gz
-rw-r--r--. 1 root root 546 Aug 7 06:25 hdfs-site.xml
建立镜像：
docker build -t "centos-hadoop" .
查看镜像：
[root@centos-docker centos-hadoop]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE centos-hadoop latest 64b9d221973b 29 minutes ago 930 MB centos-jdk-ssh latest 5286623a6cc0 About an hour ago 600 MB centos-jdk latest ad1110b84433 2 hours ago 503 MB
建立容器测试镜像：
[root@centos-docker centos-hadoop]# docker run -it centos-hadoop /bin/bash #开启容器 [root@889d94ef9cbc /]#/usr/sbin/sshd #开启sshd服务 [root@889d94ef9cbc /]# hdfs namenode -format #格式化namenode 16/08/06 22:56:34 INFO namenode.NameNode: STARTUP_MSG: /************************************************************ STARTUP_MSG: Starting NameNode STARTUP_MSG: host = 889d94ef9cbc/172.17.0.2 STARTUP_MSG: args = [-format] STARTUP_MSG: version = 2.6.0 ............................................................ 16/08/06 22:56:36 INFO common.Storage: Storage directory /data/hadoop/dfs/name has been successfully formatted. 16/08/06 22:56:37 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0 16/08/06 22:56:37 INFO util.ExitUtil: Exiting with status 0 16/08/06 22:56:37 INFO namenode.NameNode: SHUTDOWN_MSG: /************************************************************ SHUTDOWN_MSG: Shutting down NameNode at 889d94ef9cbc/172.17.0.2 ************************************************************/ [root@889d94ef9cbc /]# start-dfs.sh # 开启hdfs [root@889d94ef9cbc /]# jps #查看开启的应用程序 576 SecondaryNameNode 410 DataNode 684 Jps 328 NameNode [root@889d94ef9cbc /]# hadoop dfsadmin -report #查看HDFS状况 DEPRECATED: Use of this script to execute hdfs command is deprecated. Instead use the hdfs command for it. Configured Capacity: 10726932480 (9.99 GB) Present Capacity: 9748041728 (9.08 GB) DFS Remaining: 9748037632 (9.08 GB) DFS Used: 4096 (4 KB) DFS Used%: 0.00% Under replicated blocks: 0 Blocks with corrupt replicas: 0 Missing blocks: 0 ------------------------------------------------- Live datanodes (1): Name: 127.0.0.1:50010 (localhost) Hostname: 889d94ef9cbc Decommission Status : Normal Configured Capacity: 10726932480 (9.99 GB) DFS Used: 4096 (4 KB) Non DFS Used: 978890752 (933.54 MB) DFS Remaining: 9748037632 (9.08 GB) DFS Used%: 0.00% DFS Remaining%: 90.87% Configured Cache Capacity: 0 (0 B) Cache Used: 0 (0 B) Cache Remaining: 0 (0 B) Cache Used%: 100.00% Cache Remaining%: 0.00% Xceivers: 1 Last contact: Sat Aug 06 23:29:09 UTC 2016
5. 将前边的步骤合在一起，用一个Dockerfile 来完成
建立一个新的文件夹，文件夹要包含建立进行所需的资源。
[root@centos-docker centos-hadoop]# ll total 340616 -rw-r--r--. 1 root root 403 Aug 7 06:52 core-site.xml -rw-r--r--. 1 root root 812 Aug 7 18:04 Dockerfile -rwxr-x---. 1 root root 195257604 Aug 7 04:44 hadoop-2.6.0.tar.gz -rw-r--r--. 1 root root 546 Aug 7 06:25 hdfs-site.xml -rwxr-x---. 1 root root 153512879 Aug 7 18:14 jdk-7u79-linux-x64.tar.gz
Dockerfile中的内容为：
# build a new hadoop image with basic centos FROM centos # who is the author MAINTAINER amei # install some important softwares RUN yum -y install openssh-server openssh-clients net-tools which ####################Configurate JDK################################ # make a new directory to store the jdk files RUN mkdir /usr/local/java # copy the jdk archive to the image,and it will automaticlly unzip the tar file ADD jdk-7u79-linux-x64.tar.gz /usr/local/java/ # make a symbol link RUN ln -s /usr/local/java/jdk1.7.0_79 /usr/local/java/jdk ###################Configurate SSH################################# #generate key files RUN ssh-keygen -q -t rsa -b 2048 -f /etc/ssh/ssh_host_rsa_key -N '' RUN ssh-keygen -q -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key -N '' RUN ssh-keygen -q -t dsa -f /etc/ssh/ssh_host_ed25519_key -N '' # login localhost without password RUN ssh-keygen -f /root/.ssh/id_rsa -N '' RUN cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys ###################Configurate Hadoop############################## # copy the hadoop archive to the image,and it will automaticlly unzip the tar file ADD hadoop-2.6.0.tar.gz /usr/local/ # make a symbol link RUN ln -s /usr/local/hadoop-2.6.0 /usr/local/hadoop # copy the configuration file to image COPY core-site.xml /usr/local/hadoop/etc/hadoop/ COPY hdfs-site.xml /usr/local/hadoop/etc/hadoop/ # change hadoop environment variables RUN sed -i "s?JAVA_HOME=${JAVA_HOME}?JAVA_HOME=/usr/local/java/jdk?g" /usr/local/hadoop/etc/hadoop/hadoop-env.sh ################### Integration configuration ####################### # set environment variables ENV JAVA_HOME /usr/local/java/jdk ENV JRE_HOME ${JAVA_HOME}/jre ENV CLASSPATH .:${JAVA_HOME}/lib:${JRE_HOME}/lib ENV HADOOP_HOME /usr/local/hadoop ENV PATH ${HADOOP_HOME}/bin:${HADOOP_HOME}/sbin:${JAVA_HOME}/bin:$PATH # set password of root RUN echo "root:1234" | chpasswd # when start a container it will be executed CMD ["/usr/sbin/sshd"]
以此Dockerfile来建立Hadoop镜像
docker build -t "centos-hadoop" .
6. 后话
Dockerfile和jdk,hadoop文件以及其它的配置文件都打包好放在百度云上，解压之后可以直接在目录中敲入命令 docker build -t "centos-hadoop" . 建立Hadoop镜像，不过前提是你得先有一个centos镜像。