之前写过一个在Asp.Net Core里调用System.Drawing.Common绘图的DEMO，部署到Docker里运行，需要更新Asp.Net Core镜像的操作系统。
https://www.cnblogs.com/sunnytrudeau/p/9384620.html
当时用的阿里云的源
RUN echo "deb http://mirrors.aliyun.com/debian wheezy main contrib non-free \ deb-src http://mirrors.aliyun.com/debian wheezy main contrib non-free \ deb http://mirrors.aliyun.com/debian wheezy-updates main contrib non-free \ deb-src http://mirrors.aliyun.com/debian wheezy-updates main contrib non-free \ deb http://mirrors.aliyun.com/debian-security wheezy/updates main contrib non-free \ deb-src http://mirrors.aliyun.com/debian-security wheezy/updates main contrib non-free" > /etc/apt/sources.list
最近再次跑这个Demo，居然不好使了，更新系统无效了，创建容器失败：
Step 4/11 : RUN apt-get update
---> Running in 69abe26c3b35
Ign:1 http://mirrors.aliyun.com/debian wheezy InRelease
Ign:2 http://mirrors.aliyun.com/debian wheezy Release
Ign:3 http://mirrors.aliyun.com/debian wheezy/deb all Packages
……
Ign:14 http://mirrors.aliyun.com/debian wheezy/http://mirrors.aliyun.com/debian amd64 Packages
Reading package lists...
W: The repository 'http://mirrors.aliyun.com/debian wheezy Release' does not have a Release file.
E: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/non-free/binary-amd64/Packages 404 Not Found [IP: 124.203.224.198 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.
ERROR: Service 'myweb' failed to build: The command '/bin/sh -c apt-get update' returned a non-zero code: 100
百度学习了一下，才知道Asp.Net Core的Docker镜像是基于debian这个Linux发行版构建的，以前用的版本是wheezy，现在用的新版本是stretch
版本号以及代号 发布日期
7 wheezy 2013年5月4日
8 Jessie 2015年4月26日
9 stretch 2017年06月17日
所以，更新操作系统的源相应的更换一下就可以了。
RUN echo "deb http://mirrors.aliyun.com/debian stretch main contrib non-free \ deb-src http://mirrors.aliyun.com/debian stretch main contrib non-free \ deb http://mirrors.aliyun.com/debian stretch-updates main contrib non-free \ deb-src http://mirrors.aliyun.com/debian stretch-updates main contrib non-free \ deb http://mirrors.aliyun.com/debian-security stretch/updates main contrib non-free \ deb-src http://mirrors.aliyun.com/debian-security stretch/updates main contrib non-free \ deb http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib \ deb-src http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib" > /etc/apt/sources.list
可以进入运行中的Asp.Net Core容器查看操作系统版本
[root@localhost ~]# docker exec -it fd70cac69589 /bin/bash
root@fd70cac69589:/app# cat /etc/issue
Debian GNU/Linux 9 \n \l