从零制作一个docker的镜像

        近期docker的镜像仓库不好用了，很多国内的源也无法使用了，所有今天给大家分享一下怎么从零制作一个CentOS镜像。

准备CentOS7最小环境

mkdir /centos7.9-root

# 在该目录准备centos的最小环境
sudo yum --installroot=/centos7.9-root --releasever=7 install -y centos-release
sudo yum --installroot=/centos7.9-root --releasever=7 groupinstall -y "Core"

构建镜像

mkdir centos7
cd centos7
mv /centos7.9-root ./

# 编写Dockerfile文件
# 这是Docker提供的一个相当于是空白的镜像，直接就可以用的不用下载
cat > Dockerfile << EOF
FROM scratch
ADD centos7.9-root /
CMD ["/bin/bash"]
EOF

# 构建镜像
docker build -t centos:7.9 .
[root@bogon centos7]# docker build -t centos:7.9 .
[+] Building 33.3s (5/5) FINISHED                                    docker:default
 => [internal] load build definition from Dockerfile                           0.0s
 => => transferring dockerfile: 89B                                            0.0s
 => [internal] load .dockerignore                                              0.0s
 => => transferring context: 2B                                                0.0s
 => [internal] load build context                                             14.5s
 => => transferring context: 1.37GB                                           14.5s
 => [1/1] ADD centos7.9-root /                                                 7.7s
 => exporting to image                                                        10.9s
 => => exporting layers                                                       10.9s
 => => writing image sha256:359d4c8ae6f4f9d700d847f38066f52344c628789d868e196  0.0s
 => => naming to docker.io/library/centos:7.9                                  0.0s

测试

[root@bogon ~]# docker run -it --rm centos:7.9 bash
[root@c74f76deee3d /]#