Docker镜像构建手册

简介

基础镜像构建

此处将虚拟机安装的操作系统构建为基础镜像

 # tar -cvpf /cloud/centos-7-3.tar --directory=/ --exclude=proc --exclude=sys  --excluede=dev --exclude=run --exclude=cloud / > /cloud/centos.log

 #cat centos-7-3.tar |docker import - centos:7.3

• 基于RHEL-7.3构建基础镜像

 # febootstrap -i bash -i yum -i iproute -i vi -i openssh-server -i openssh-clients -i python -i passwd -i which rhel-7.3 ./rhel-7.3 file:///mnt/cdrom/

 file:///mnt/cdrom/为yum源
 ./rhel-7.3  是生成的文件

 # tar -C /home/rhel-7.3 -c . | docker import - rhel-base:7.3

 /home/rhel-7.3 用febootstrap生成的文件（是个目录）

Dockerfile

命令

• FROM

 可以有多个
 FROM RHEL:6.3

• ENTRYPOINT

 是容器运行的入口，且要保证命令不退出，可以单独使用，也可以和CMD一起使用
 有两种模式：shell模式，exec模式
   ENTRYPOINT ["execable", "param1", "param2"]   // exec 模式
   ENTRYPOINT execable param1 param2             // shell 模式

  使用exec模式，CMD命令会作为ENTRYPOINT的参数，追加到参数列表后
  如果 ENTRYPOINT 使用了 shell 模式，CMD 指令会被忽略
  如果 ENTRYPOINT 使用了 exec 模式，CMD 也应该使用 exec 模式

exec模式样例：
COPY ./docker-entrypoint.sh /
ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["postgres"]
-------------
docker-entrypoint.sh的内容
-------------
#!/bin/bash
set -e
if [ "$1" = 'postgres' ]; then
    chown -R postgres "$PGDATA"
    if [ -z "$(ls -A "$PGDATA")" ]; then
        gosu postgres initdb
    fi
    exec gosu postgres "$@"
fi
exec "$@"

• CMD

 是容器运行的入口，且要保证命令不退出，可以单独使用，也可以和ENTRYPOINT一起使用

 备注：
    Dockerfile中必须至少有ENTRYPOINT或CMD中的一个

• COPY

 COPY --from=sampleapp:latest home/user/app/config.json app/config.json
 sampleapp:latest：镜像名称
 home/user/app/config.json：镜像中的文件
 app/config.json：复制到新镜像中的文件名

Jboss 镜像构建

Redis 镜像构建

构建命令

 # docker build -t redis:3.2.11 .

目录

 # ls -al
   Dockerfile
   cloud.repo
   docker-entrypoint.sh
   redis-3.2.11

Dockerfile

 FROM CentOS:7.6

 COPY redis-3.2.11 /opt/redis-3.2.11
 COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh

 RUN useradd redisuser -d /home/redisuser -s /bin/bash

 RUN rm -fr /etc/yum/yum.repos.d/*

 COPY cloud.repo /etc/yum/yum.repos.d/cloud.repo

 RUN yum clean all
 RUN yum makecache
 RUN yum install "crontab*" -y 

 RUN echo 'redisuser:redisuser' |chpasswd
 RUN chown -R redisuser:redisuser /opt/redis-3.2.11

 ENV REDIS_HOME /opt/redis-3.2.11
 ENV PATH ${REDIS_HOME}:$PATH
 RUN export PATH

 EXPOSE 6379

 WORKDIR /opt/redis-3.2.11/src

 ENTRYPOINT ["docker-entrypoint.sh", "redis-server"]

cloud.repo

[centos-7.3]
name=CentOS-$releasever-Base
baseurl=http://10.0.156.250/redhat7.3/x86_64
enable=1
gpgcheck=0

docker-entrypoint.sh

#!/bin/sh

set -e

if [ "${1#-}" != "$1" ] || [ "${1%.conf}" != "$1" ];then
    set -- redis-server "$@"
fi

exec "$@" 

备注： set -- "$X" 就是把X的值返回给$1, set –- $X 就是把X作为一个表达式的值一一返回

MySql 镜像构建

sonatype nexus

镜像层解析

 ADD file:6f877549795f4798a38b318c0f63f6646dbf10d3c249c7f4b73cc7cfe42dc0f5 in / 
 LABEL org.label-schema.schema-version=1.0 org.label-schema.name=CentOS Base Image org.label-schema.vendor=CentOS org.label-schema.license=GPLv2  org.label-schema.build-date=20181205
 CMD ["/bin/bash"]
 MAINTAINER Sonatype <cloud-ops@sonatype.com>
 LABEL vendor=Sonatype com.sonatype.license=Apache License, Version 2.0 com.sonatype.name=Nexus Repository Manager base image
 ARG NEXUS_VERSION=3.15.2-01
 ARG NEXUS_DOWNLOAD_URL=https://download.sonatype.com/nexus/3/nexus-3.15.2-01-unix.tar.gz
 ARG NEXUS_DOWNLOAD_SHA256_HASH=acde357f5bbc6100eb0d5a4c60a1673d5f1f785e71a36cfa308b8dfa45cf25d0
 ENV SONATYPE_DIR=/opt/sonatype
 ENV NEXUS_HOME=/opt/sonatype/nexus NEXUS_DATA=/nexus-data NEXUS_CONTEXT= SONATYPE_WORK=/opt/sonatype/sonatype-work DOCKER_TYPE=docker
 ARG NEXUS_REPOSITORY_MANAGER_COOKBOOK_VERSION=release-0.5.20190212-155606.d1afdfe
 ARG  NEXUS_REPOSITORY_MANAGER_COOKBOOK_URL=https://github.com/sonatype/chef-nexus-repository-manager/releases/download/release-0.5.20190212-155606.d1afdfe/ch ef-nexus-repository-manager.tar.gz
 ADD file:96a8726e4f3ee18b65140cf1dfb4845d98d454ceb2c45fbd846c57e32a5a2ed2 in /var/chef/solo.json.erb
 |5 NEXUS_DOWNLOAD_SHA256_HASH=acde357f5bbc6100eb0d5a4c60a1673d5f1f785e71a36cfa308b8dfa45cf25d0  NEXUS_DOWNLOAD_URL=https://download.sonatype.com/nexus/3/nexus-3.15.2-01-unix.tar.gz  NEXUS_REPOSITORY_MANAGER_COOKBOOK_URL=https://github.com/sonatype/chef-nexus-repository-manager/releases/download/release-0.5.20190212-155606.d1afdfe/ch ef-nexus-repository-manager.tar.gz NEXUS_REPOSITORY_MANAGER_COOKBOOK_VERSION=release-0.5.20190212-155606.d1afdfe NEXUS_VERSION=3.15.2-01 RUN curl -L  https://www.getchef.com/chef/install.sh | bash && /opt/chef/embedded/bin/erb /var/chef/solo.json.erb > /var/chef/solo.json && chef-solo --recipe-url  ${NEXUS_REPOSITORY_MANAGER_COOKBOOK_URL} --json-attributes /var/chef/solo.json && rpm -qa *chef* | xargs rpm -e && rpm --rebuilddb && rm -rf /etc/chef  && rm -rf /opt/chefdk && rm -rf /var/cache/yum && rm -rf /var/chef
 VOLUME [/nexus-data]
 EXPOSE 8081
 USER nexus
 ENV INSTALL4J_ADD_VM_PARAMS=-Xms1200m -Xmx1200m -XX:MaxDirectMemorySize=2g -Djava.util.prefs.userRoot=/nexus-data/javaprefs
 CMD ["sh" "-c" "${SONATYPE_DIR}/start-nexus-repository-manager.sh"]