Docker容器（二）——镜像制作

　　制作Docker镜像有两种方式：第一种、docker commit，保存容器（Container）的当前状态到镜像后，然后生成对应的image；第二种、docker build，使用Dockerfile文件自动化制作镜像。

(1).docker commit

　　启动一个实例，安装apache

[root@youxi1 ~]# docker images
REPOSITORY                     TAG                 IMAGE ID            CREATED             SIZE
centos                         latest              67fa590cfc1c        3 weeks ago         202MB
hub.c.163.com/library/tomcat   latest              72d2be374029        2 years ago         292MB
[root@youxi1 ~]# docker run -it centos:latest /bin/bash
[root@985ef7e0c4ca /]# yum -y install httpd
[root@985ef7e0c4ca /]# exit
exit

　　根据容器当前状态制作一个镜像，语法docker commit <容器ID> [仓库]:[标签]

[root@youxi1 ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                     PORTS               NAMES
985ef7e0c4ca        centos:latest       "/bin/bash"         4 minutes ago       Exited (0) 2 minutes ago                       sharp_kare
9a81af9b4134        centos:latest       "/bin/bash"         2 days ago          Exited (0) 2 days ago                          pensive_dijkstra
3ecc9bafd429        centos:latest       "/bin/bash"         2 days ago          Exited (0) 2 days ago                          sleepy_wilbur
[root@youxi1 ~]# docker commit 985ef7e0c4ca centos:httpd
sha256:bdd371e6f1cf035bd501c09b28a2b2827900973a0defa9e35eadcd2f2f55e5e4
[root@youxi1 ~]# docker images
REPOSITORY                     TAG                 IMAGE ID            CREATED             SIZE
centos                         httpd               bdd371e6f1cf        14 seconds ago      346MB
centos                         latest              67fa590cfc1c        3 weeks ago         202MB
hub.c.163.com/library/tomcat   latest              72d2be374029        2 years ago         292MB

　　启动新创建的镜像，查看是否存在httpd服务

[root@youxi1 ~]# docker run -it centos:httpd /bin/bash
[root@34ac01c03fe3 /]# rpm -qa httpd　　//可以看到是存在的
httpd-2.4.6-89.el7.centos.1.x86_64

(2).docker build

　　使用docker build创建镜像时，需要使用Dockerfile文件自动化制作镜像。Dockerfile类似源码编译./configure后产生的Makefile。

　　创建工作目录，制作Dockerfile

[root@youxi1 ~]# mkdir /docker-build
[root@youxi1 ~]# vim /docker-build/Dockerfile
FROM centos:latest　　#以哪个镜像为基础
MAINTAINER <youxi@163.com>　　#镜像创建者
RUN yum -y install httpd　　#运行安装httpd命令
ADD start.sh /usr/local/bin/start.sh　　#将本地文件拷贝到镜像中，权限为0755（？），uid和gid为0
ADD index.html /var/www/html/index.html
CMD /usr/local/bin/start.sh　　#实例启动后执行的命令，一般跟需要开机启动的服务或脚本

　　创建start.sh和index.html

[root@youxi1 ~]# echo "/usr/sbin/httpd -DFOREGROUND" > /docker-build/start.sh
[root@youxi1 ~]# chmod +x /docker-build/start.sh
[root@youxi1 ~]# echo "docker image build test" > /docker-build/index.html

　　删除已有的centos:httpd

[root@youxi1 ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                         PORTS               NAMES
34ac01c03fe3        centos:httpd        "/bin/bash"         About an hour ago   Exited (0) 43 minutes ago                          gifted_cerf
985ef7e0c4ca        centos:latest       "/bin/bash"         About an hour ago   Exited (0) About an hour ago                       sharp_kare
9a81af9b4134        centos:latest       "/bin/bash"         2 days ago          Exited (0) 2 days ago                              pensive_dijkstra
3ecc9bafd429        centos:latest       "/bin/bash"         2 days ago          Exited (0) 2 days ago                              sleepy_wilbur
[root@youxi1 ~]# docker stop 34ac01c03fe3
34ac01c03fe3
[root@youxi1 ~]# docker rm 34ac01c03fe3
34ac01c03fe3
[root@youxi1 ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                         PORTS               NAMES
985ef7e0c4ca        centos:latest       "/bin/bash"         About an hour ago   Exited (0) About an hour ago                       sharp_kare
9a81af9b4134        centos:latest       "/bin/bash"         2 days ago          Exited (0) 2 days ago                              pensive_dijkstra
3ecc9bafd429        centos:latest       "/bin/bash"         2 days ago          Exited (0) 2 days ago
[root@youxi1 ~]# docker rmi centos:httpd
Untagged: centos:httpd
Deleted: sha256:bdd371e6f1cf035bd501c09b28a2b2827900973a0defa9e35eadcd2f2f55e5e4
Deleted: sha256:e5f250b390d99269c53a6150c776f5af4e74b965f4c86977fea7582b9e624870
[root@youxi1 ~]# docker images
REPOSITORY                     TAG                 IMAGE ID            CREATED             SIZE
centos                         latest              67fa590cfc1c        3 weeks ago         202MB
hub.c.163.com/library/tomcat   latest              72d2be374029        2 years ago         292MB

　　使用build创建新的镜像，语法docker build -t [仓库名]:[标签] [Dockerfile文件路径]

[root@youxi1 ~]# docker build -t centos:httpd /docker-build/
[root@youxi1 ~]# docker images
REPOSITORY                     TAG                 IMAGE ID            CREATED              SIZE
centos                         httpd               565f0e4e1ef3        About a minute ago   346MB
centos                         latest              67fa590cfc1c        3 weeks ago          202MB
hub.c.163.com/library/tomcat   latest              72d2be374029        2 years ago          292MB

(3).Docker镜像发布

　1）发布到本地

　　语法：docker save  -o [tar包名] [仓库名]:[标签]

[root@youxi1 ~]# docker save -o docker.id-centos-httpd-image.tar centos:httpd
[root@youxi1 ~]# ll -h
总用量 346M
-rw-------. 1 root root 1.6K 5月  14 09:20 anaconda-ks.cfg
-rw-------  1 root root 339M 9月  14 15:26 docker.id-centos-httpd-image.tar

　2）发布到网上

　　一般先到https://hub.docker.com/（DockerHub）上注册一个账号，并创建一个存储库

　　使用命令登录

[root@youxi1 ~]# docker login -u [用户名] -p [密码]
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
 
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
 
Login Succeeded

　　上传镜像。注意：上传前需要修改仓库名，否则上传有问题。

[root@youxi1 ~]# docker tag centos:httpd ghhh4512/centos:httpd　　//这里的ghhh4512是我的Docker用户名,centos是建立的存储库
[root@youxi1 ~]# docker push ghhh4512/centos:httpd
The push refers to repository [docker.io/ghhh4512/centos]
7873e44b6044: Pushed
0e86f20c1056: Pushed
b3e0fc83922e: Pushed
877b494a9f30: Pushed
httpd: digest: sha256:464ffb58cbc2334a936bea7081db41b257afb5b21dfcce6dd27863dc9b777855 size: 1155