docker续3：dockerfile

news2024/9/21 16:25:28

一、使用Dockerfile创建应用镜像

在Docker file中定义所需要执⾏的指令，使⽤ docker build创建镜像，过程中会按照dockerfile所定义的内容进⾏打开临时性容器，把docker file中命令全部执⾏完成，就得到了⼀个容器应⽤镜像，每⼀⾏命令都会出现容器，都会使⽤docker commit进⾏提交⼀个临时性的镜像

1.Docker file关键字

1.FORM 指定基础镜像为该镜像的最后修改版本
2.FROM <image :tag>指定基础镜像为该镜像的⼀个tag版本
3.MAINTAINER 指定镜像创建者，企业内部不⽤指定，对外发布也可以不指定
3.RUN 运⾏命令，安装软件
4.CMD 设置container启动时进⾏的操作，如果容器镜像中有这
个命名，启动容器时，不要⼿动让容器执⾏其他命令
5.ENTRYPORINT（⼊⼝点）cmd每次只能执⾏⼀个指令，entrypoint可以多⾏执⾏。
6.USER设置容器进程的⼀些⽤户
7.EXPOSE 暴露端⼝指定容器需要映射到宿主机的端⼝
8.ENV 设置环境变量 -e
9.ADD 从宿主机src复制⽂件到容器的dest路径
10.volumn 指定挂载点
11.WROKDIR 切换⽬录
12.ONBUILD在⼦镜像中执⾏指令

2.dockerfile应用

（1）httpd

[root@localhost ~]# systemctl start docker
[root@localhost ~]# docker ps --all
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
[root@localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos latest 5d0da3dc9764 2 years ago 231MB
[root@localhost ~]# mkdir httpd0 //创建⼀个⽬录，⽤于存储Docker file所使⽤的⽂件
[root@localhost ~]# cd httpd0/ // 在此⽬录中创建Docker file⽂件，以及镜像制作所使⽤的⽂件
[root@localhost httpd0]# vim abc.sh //编辑启动脚本
#!/bin/bash
rm -rf /run/*httpd*
exec /sbin/httpd -D FOREGROUND
[root@localhost httpd0]# echo "httpd server is running" > index.html //编辑index.html文件
[root@localhost httpd0]# vim Dockerfile //首字母必须大写
FROM centos:latest

MAINTAINER "我是你爸爸"

RUN rm -rf /etc/yum.repos.d/* && curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo

RUN yum clean all && yum makecache

RUN yum -y install epel-release

RUN yum -y install httpd

ADD index.html /var/www/html/index.html

ADD abc.sh /abc.sh

RUN chmod -v +x /abc.sh

EXPOSE 80

WORKDIR /

CMD ["/bin/bash","/abc.sh"]
[root@localhost httpd0]# ls //这里看到三个文件已经被创建成功
abc.sh Dockerfile index.html
[root@localhost httpd0]# docker build -t centos:httpd0 . //使用docker build创建镜像,后面有个点，别忘了
[root@localhost httpd0]# docker images //查看镜像
REPOSITORY TAG IMAGE ID CREATED SIZE
centos httpd0 47671b410a9b 12 seconds ago 280MB
centos latest 5d0da3dc9764 2 years ago 231MB
[root@localhost httpd0]# docker run -it --name c1 -p80:80 centos:httpd0 /bin/bash //使用创建的镜像启动容器
bfe452a31fc8f29819ca706165ea18ff2b167bbc956dd92081bb31443a5c566e
[root@7d4bca85353f /]# httpd -k start
[root@7d4bca85353f /]# curl localhost
httpd server is running
ctrl+p+q退出

（2）nginx

[root@localhost httpd0]# vim Dockerfile
FROM centos:latest

MAINTAINER "nginx"

RUN rm -rf /etc/yum.repos.d/* && curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo

RUN yum clean all && yum makecache

RUN yum -y install epel-release

RUN yum -y install nginx

RUN echo "daemon off;" >> /etc/nginx/nginx.conf #这个指令的作用是告诉 Nginx 以非守护进程（foreground，前台）模式运行，而不是默认的守护进程（daemon，后台）模式。在前台运行 Nginx 在调试时非常有用，因为这样可以直接看到输出和错误信息，而不需要查看后台的日志文件。

EXPOSE 80

WORKDIR /

CMD /usr/sbin/nginx
[root@localhost httpd0]# docker build -t centos:nginx . //创建镜像
[root@localhost httpd0]# docker run -d --name c0 -p80:80 -v /opt/:/usr/share/nginx/html/ centos:nginx //隐藏启动并映射端口，挂载文件
2dd6dc32ee8085993681a69fa9d7850a66ce04586129e2724cec7558de582958
[root@localhost httpd0]# docker ps --all
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2dd6dc32ee80 centos:nginx "/bin/sh -c /usr/sbi…" 11 seconds ago Up 10 seconds 0.0.0.0:80->80/tcp, :::80->80/tcp c0
[root@localhost httpd0]# curl 192.168.1.76
真机浏览器访问192.168.1.76

二、创建私有镜像仓库

[root@localhost httpd0]# docker images //现在有两个自建的镜像（nginx，httpd0）
REPOSITORY TAG IMAGE ID CREATED SIZE
centos nginx 189a0a502919 41 minutes ago 401MB
centos httpd0 b91c1a8e080f About an hour ago 338MB
centos latest 5d0da3dc9764 2 years ago 231MB
[root@localhost httpd0]# docker pull registry //拉取registry（安装仓库镜像）
[root@localhost httpd0]# cd
[root@localhost ~]# mkdir /regist //创建挂载目录
[root@localhost ~]# docker run -d --name r2 -v /regist/:/var/lib/registry -p5000:5000 registry:latest //启动容器，映射端口，挂载目录
ddad689d0dab4fa6c2c199e28fc08b2830ab42e6ba082528bfacd523808cff58
[root@localhost ~]# docker ps --all
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ddad689d0dab registry:latest "/entrypoint.sh /etc…" 4 seconds ago Up 4 seconds 0.0.0.0:5000->5000/tcp, :::5000->5000/tcp r2
[root@localhost ~]# curl http://192.168.1.76:5000/v2/_catalog //访问仓库
{"repositories":[]}
[root@localhost ~]# vim /etc/docker/daemon.json //添加仓库
{
"registry-mirrors": [
   "https://do.nark.eu.org",
   "https://dc.j8.work",
   "https://docker.m.daocloud.io",
   "https://dockerproxy.com",
   "https://docker.mirrors.ustc.edu.cn",
   "https://docker.nju.edu.cn"
],

   "hosts": [
       "tcp://0.0.0.0:2375",
       "unix:///var/run/docker.sock"
   ],
   "insecure-registries":[
       "http://192.168.1.76:5000"
   ]
}
[root@localhost ~]# systemctl restart docker //重启docker
[root@localhost ~]# docker start r2 //启动registry容器
[root@localhost ~]# curl http://192.168.1.76:5000/v2/_catalog //重新访问仓库测试
{"repositories":[]}
[root@localhost ~]# docker tag centos:httpd0 192.168.1.76:5000/centos:httpd //为要上传的镜像打标记
[root@localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos nginx 189a0a502919 About an hour ago 401MB
192.168.1.76:5000/centos httpd b91c1a8e080f 2 hours ago 338MB
centos httpd0 b91c1a8e080f 2 hours ago 338MB
registry latest cfb4d9904335 10 months ago 25.4MB
centos latest 5d0da3dc9764 2 years ago 231MB
[root@localhost ~]# docker push 192.168.1.76:5000/centos:httpd //推送（上传）出去
[root@localhost ~]# curl http://192.168.1.76:5000/v2/_catalog //访问仓库，这里看到镜像已经上传成功了
{"repositories":["centos"]}