1. 前言
本文详细介绍如何基于kylin v10 ISO文件构建出docker image。系统环境如下：
dockder: 20.10.7
linux os: kylinv 10 (GFB)
linux kernel: 4.19.90-52.23.v2207.gfb01.ky10.aarch64
2. 构建yum离线源
2.1. 挂载ISO文件
mount Kylin-Server-V10-GFB-Release-030-ARM64.iso /media
2.2. 添加离线repo文件
在/etc/yum.repos.d/下创建kylin-local.repo，并添加如下内容
[kylin-local]
name = Kylin Local
baseurl = file:///media/
gpgcheck = 0
enabled = 1
2.3. 生成元数据缓存
dnf clean all && dnf makecache
3. 构建系统环境
3.1. 创建系统安装目录
mkdir -p /opt/kylin-minimal
3.2. 安装最小系统
dnf groupinstall "Minimal" --installroot /opt/kylin-minimal
3.3. 验证系统环境
执行chroot /opt/kylin-minimal命令进入最小系统的根目录，执行ll命令查看目录结构。
[root@node0 /]# ll
total 16
lrwxrwxrwx 1 root root 7 Apr 2 2021 bin -> usr/bin
dr-xr-xr-x 7 root root 4096 Jan 3 08:58 boot
drwxr-xr-x 2 root root 42 Jan 3 08:57 dev
drwxr-xr-x 88 root root 8192 Jan 3 08:58 etc
drwxr-xr-x 2 root root 6 Apr 2 2021 home
lrwxrwxrwx 1 root root 7 Apr 2 2021 lib -> usr/lib
lrwxrwxrwx 1 root root 9 Apr 2 2021 lib64 -> usr/lib64
drwxr-xr-x 2 root root 6 Apr 2 2021 media
drwxr-xr-x 2 root root 6 Apr 2 2021 mnt
drwxr-xr-x 2 root root 6 Apr 2 2021 opt
dr-xr-xr-x 2 root root 6 Apr 2 2021 proc
dr-xr-x--- 2 root root 140 Jan 3 08:59 root
drwxr-xr-x 16 root root 281 Jan 3 08:56 run
lrwxrwxrwx 1 root root 8 Apr 2 2021 sbin -> usr/sbin
drwxr-xr-x 2 root root 6 Apr 2 2021 srv
dr-xr-xr-x 2 root root 6 Apr 2 2021 sys
drwxrwxrwt 2 root root 6 Jan 3 08:58 tmp
drwxr-xr-x 12 root root 192 Jan 3 08:55 usr
drwxr-xr-x 19 root root 332 Jan 3 08:56 var
如果显示以上目录结构，则说明最小系统环境安装成功。
4. 构建docker镜像
4.1. 打包系统安装目录
tar -C /opt/kylin-minimal -cvpf /opt/kylin-minimal.tar .
4.2. 创建镜像
cat /opt/kylin-minimal.tar | docker import - kylin-minimal:v10
根据官方文档介绍，从零构建镜像只有2种方式：FROM scratch和using tar。FROM scratch是构建一个空白的镜像，没有任何内容。而using tar是基于tar包构建的镜像。上述命令是从kylin-minimal tar包构建docker镜像。镜像名称为kylin-minimal，标签为v10。
4.3. 查看镜像
docker images ls -a
--------------------
REPOSITORY TAG IMAGE ID CREATED SIZE
kylin-minimal v10 4746e82d9656 1 days ago 2.0GB
5. 参考资料
- https://docs.docker.com/build/building/base-images/
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