docker mirrored (apache, systemctl, ssh)

Docker mirrored

This chapter structure

• Docker layered mirror
• The basic method of creating Dockerfile
• Dockerfile create applications container

Docker layered mirror

Each instruction Dockerfile creates a new image layer

Mirror layer will be cached and reused

When the modified instruction Dockerfile, copied files changed, or mirror constructed specified variable is different, the corresponding mirrored cache will fail

After a layer of mirrored cache fails, it will fail the buffer layer mirror

Mirror layer is immutable, if a file is added in one layer, and then delete it in the next layer, the mirror will still contain the file

Docker create mirrored

Docker Mirror

• It is the standard format for application release
• Docker container may support a run

  Create a method Docker mirror

• Based on the existing image creation
• Create a template-based local
• Based Dockerfile create

  Based on the existing image creation

  The program running inside the container packed operating environment and generate a new image

docker create -it centos /bin/bash
docker commit -m "new" -a "daoke" a19597abf62d daoke:centos

• -m: Information Description
• -a: Author Information
• -p: generating a stop during operation of the vessel

  Create a template-based local

  Generating a new operating system image by importing the template file

  Use wget command to import a local mirroring

wget http://123.56.134.27/pub/package/LAMP-C7/nginx-1.12.0.tar.gz

cat nginx-1.12.0.tar.gz | docker import - docker：new

After successful import you can view information about local mirror

docker images | grep new

Based Dockerfile create

Dockerfile is a file consisting of a set of instructions

Dockerfile result of four parts

• Basic information affecting
• Maintainer information
• Mirror operation instruction
• When the container starts execution instruction

  Use Dockerfile create a mirror and run in a container

  instruction	meaning
  FROM Mirror	Specifies the new image is based on a mirror, must be the first instruction FROM instruction, each will need to create a mirror image FFROM instruction.
  MAINTAINER name	Description of the new mirror maintainer information
  RUN command	Executed on the basis of the mirror command, and submit to the new mirror
  The CMD [ "program to be run", "parameter 1" parameter 2 "]	Commands or command scripts to run at startup container, Dockerfile only a CMD command, if you specify more than can only be executed last f
  EXPOSE port number	When specify a new image is loaded into the Docker to open ports
  ENV environment variable variable values	Set an environment variable value, will be used later in RUN
  ADD source file / directory target file / directory	Copy the source file to the target file, the source file to be located in the same directory with the Dockerfile, or f URL
  COPY source file / directory target file / directory	Copy the file / directory on the local host to the target location, source file / directory to the same directory in DGckerfile
  VOLUME [ "directory"]	Create a mount point in the container
  USER username / UID	When the user runs the specified container
  WORKDIR path	For subsequent RUN, CMD, ENTRYPOINT specify the working directory
  ONBUILD command	The command specifies the generated image as a basis to run mirroring
  HEALTHCHECK	health examination

Dockerfile create applications container

Dockerfile create mirror container apache

mkdir apache
cd apache/
vim Dockerfile
#基于的基础镜像
FROM centos
#维护镜像的用户信息
MAINTAINER The project <cloude-docker>
#镜像操作指令安装apache软件
RUN yum -y update //更新yum仓库
RUN yum -y install httpd
#开启80端口
EXPOSE 80
#复制网站首页文件
ADD index.html /var/www/html/index.html
#将执行脚本复制到镜像中
ADD run.sh /run.sh
RUN chmod 755 /run.sh
#启动容器时执行脚本
CMD ["/run.sh"]

[root@localhost opt]# vim run.sh
#!/bin/bash
rm -rf /run/httpd/*
exec /usr/sbin/apachectl -D FOREGROUND

echo "this is web" index.html
//生成镜像
docker build -t httpd:centos .
//新镜像运行容器
docker run -d -p 1216:80 httpd:centos

Dockerfile create mirror container ssh

mkdir sshd
cd sshd/
vim Dockerfile
#基于的基础镜像
FROM centos
#维护镜像的用户信息
MAINTAINER this is project  <lzp-sshd>
#重新加载yum源
RUN yum -y update
#安装必要软件包
RUN yum -y install openssh* net-tools lsof telnet passwd
#为root用户设置密码
RUN echo '123456' | passwd --stdin root
#修改配置文件
RUN sed -i 's/UsePAM yes/UsePAM no/g' /etc/ssh/sshd_config
#生成秘钥
RUN ssh-keygen -t rsa -f /etc/ssh/sshd_host_rsa_key
RUN sed -i '/^scssion\s\+required\s\+pam_loginuid.so/s/^/#/' /etc/pam.d/sshd
RUN mkdir -P /root/.ssh && chown root.root /root && chmod 700 /root/.ssh
#开启20端口
EXPOSE 22
#启动容器
CMD ["/usr/sbin/sshd","-D"]

//生成镜像
docker build -t sshd:new .
//启动容器并修改root密码
docker run -d -P sshd:new
ssh localhost -p 32770

Dockerfile create systemctl mirror image of the container vessel based sshd

mkdir systemctl 
cd systemctl 
vim Dockerfile
#基于的基础镜像
FROM sshd:new
ENV container docker
RUN (cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == \
systemd-tmpfile-setup.service ] || rm -f $i; done); \
rm -f /lib/systemd/system/multi-user.target.wants/*; \
rm -f /etc/systemd/system/*.wants/*; \
rm -f /lib/systemd/system/local-fs.target.wants/*; \
rm -f /lib/systemd/system/sockets.target.wants/*udev*; \
rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \
rm -f /lib/systemd/system/basic.target.wants/*; \
rm -f /lib/systemd/system/anaconda.target.wants/*;
VOLUME [ "/sys/fs/cgroup" ]
CMD ["/usr/sbin/init"]

//生成镜像
docker build -t local/c7-systemd:latest .

//privileged container内的root拥有真正的root权限。否责，container内的root只是外部的一个普通用户权限
docker run --privileged -ti -v /sys/fs/cgroup:sys/fs/cgroup:ro local/c7-systemd:latest /sbin/init
//进入容器 
docker exec -it    镜像IP   bash