引言：docker镜像的构建对于程序开发者来说是十分友好的，由于在Dockerfile的过程踩了坑，下面就记录一下创建hadoop镜像的过程。

首先先创建一个文件命名Dockerfile

我们需要一个基础镜像，在这里我们有个alpine的小型镜像，里面支持JDK1.8

在同目录下添加几个文件

bootstrap.sh:镜像启动执行的脚本（ssh hadoop namenode -format，hadoop中username等）

hadoop-2.7.7.tar.gz:hadoop的下载包
hadoop-native-64-2.7.0.tar:hadoop 本地包
core-site.xml/yarn-site.xml/hdfs-site.xml:自己定义要替换的xml文件

Dockerfile内容

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
FROM xiaoyuzhang321/因:8-jdk-alpine
MAINTAINER xiaoyu xiaoyuzhang321@gmail.com
USER root

# install dev tools
RUN apk add curl which tar sudo openssh-server openssh-client rsync
# update libselinux. see https://github.com/sequenceiq/hadoop-docker/issues/14
RUN apk update libselinux

# passwordless ssh
RUN sed -i "s/#PermitRootLogin.*/PermitRootLogin yes/g" /etc/ssh/sshd_config && \
    sed -i 's?/root:/bin/ash?/root:/bin/bash?g' /etc/passwd && \
    ssh-keygen -t dsa -P "" -f /etc/ssh/ssh_host_dsa_key && \
    ssh-keygen -t rsa -P "" -f /etc/ssh/ssh_host_rsa_key && \
    ssh-keygen -t ecdsa -P "" -f /etc/ssh/ssh_host_ecdsa_key && \
    ssh-keygen -t ed25519 -P "" -f /etc/ssh/ssh_host_ed25519_key && \
    echo "root:123" | chpasswd

ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
ENV PATH $PATH:$JAVA_HOME/bin

# download native support
RUN mkdir -p /tmp/native
RUN curl -Ls http://dl.bintray.com/sequenceiq/sequenceiq-bin/hadoop-native-64-2.7.0.tar | tar -x -C /tmp/native

# hadoop
#RUN curl -s http://www.eu.apache.org/dist/hadoop/common/hadoop-2.7.7/hadoop-2.7.7.tar.gz | tar -xz -C /usr/local/
ADD hadoop-2.7.7.tar.gz /usr/local/
RUN cd /usr/local && ln -s ./hadoop-2.7.7 hadoop

ENV HADOOP_PREFIX /usr/local/hadoop
ENV HADOOP_COMMON_HOME /usr/local/hadoop
ENV HADOOP_HDFS_HOME /usr/local/hadoop
ENV HADOOP_MAPRED_HOME /usr/local/hadoop
ENV HADOOP_YARN_HOME /usr/local/hadoop
ENV HADOOP_CONF_DIR /usr/local/hadoop/etc/hadoop
ENV YARN_CONF_DIR $HADOOP_PREFIX/etc/hadoop

RUN sed -i '/^export JAVA_HOME/ s:.*:export JAVA_HOME=/usr/lib/jvm/java-1.8-openjdk HADOOP_PREFIX=/usr/local/hadoop\nexport HADOOP_HOME=/usr/local/hadoop\n:' $HADOOP_PREFIX/etc/hadoop/hadoop-env.sh
RUN sed -i '/^export HADOOP_CONF_DIR/ s:.*:export HADOOP_CONF_DIR=/usr/local/hadoop/etc/hadoop/:' $HADOOP_PREFIX/etc/hadoop/hadoop-env.sh
#RUN . $HADOOP_PREFIX/etc/hadoop/hadoop-env.sh

RUN mkdir $HADOOP_PREFIX/input
RUN cp $HADOOP_PREFIX/etc/hadoop/*.xml $HADOOP_PREFIX/input

# pseudo distributed
ADD core-site.xml.template $HADOOP_PREFIX/etc/hadoop/core-site.xml.template
RUN sed s/HOSTNAME/localhost/ /usr/local/hadoop/etc/hadoop/core-site.xml.template > /usr/local/hadoop/etc/hadoop/core-site.xml
ADD hdfs-site.xml $HADOOP_PREFIX/etc/hadoop/hdfs-site.xml
#ADD mapred-site.xml $HADOOP_PREFIX/etc/hadoop/mapred-site.xml
ADD yarn-site.xml $HADOOP_PREFIX/etc/hadoop/yarn-site.xml

RUN $HADOOP_PREFIX/bin/hdfs namenode -format

# fixing the libhadoop.so like a boss
RUN rm -rf /usr/local/hadoop/lib/native
RUN mv /tmp/native /usr/local/hadoop/lib

ADD ssh_config /root/.ssh/config
RUN chmod 600 /root/.ssh/config
RUN chown root:root /root/.ssh/config

ADD bootstrap.sh /etc/bootstrap.sh
RUN chown root:root /etc/bootstrap.sh
RUN chmod 700 /etc/bootstrap.sh

ENV BOOTSTRAP /etc/bootstrap.sh

# workingaround docker.io build error
RUN ls -la /usr/local/hadoop/etc/hadoop/*-env.sh
RUN chmod +x /usr/local/hadoop/etc/hadoop/*-env.sh
RUN ls -la /usr/local/hadoop/etc/hadoop/*-env.sh

# fix the 254 error code
RUN sed  -i "/^[^#]*UsePAM/ s/.*/#&/"  /etc/ssh/sshd_config
#RUN echo "UsePAM no" >> /etc/ssh/sshd_config
RUN echo "Port 2122" >> /etc/ssh/sshd_config

#RUN /usr/sbin/sshd && $HADOOP_PREFIX/etc/hadoop/hadoop-env.sh && $HADOOP_PREFIX/sbin/start-dfs.sh && $HADOOP_PREFIX/bin/hdfs dfs -mkdir -p /user/root
#RUN /usr/sbin/sshd && $HADOOP_PREFIX/etc/hadoop/hadoop-env.sh && $HADOOP_PREFIX/sbin/start-dfs.sh && $HADOOP_PREFIX/bin/hdfs dfs -put $HADOOP_PREFIX/etc/hadoop/ input

#CMD ["/etc/bootstrap.sh", "-d"]

# Hdfs ports
EXPOSE 50010 50020 50070 50075 50090
# Mapred ports
EXPOSE 19888
#Yarn ports
EXPOSE 8030 8031 8032 8033 8040 8042 8088
#Other ports
EXPOSE 49707 2122

Dockerfile里面包含了ssh配置，hadoop配置（jdk，端口，配置文件等）

Dockerfile里面继承了好多命令（ADD RUN COPY ENV），ADD与COPY的区别是前者可以解压压缩包，以上实验需求记录的过程。