Docker容器执行apt-get update出现404错误的原因排查

使用php:5.5.38-apache Docker镜像，进入容器执行apt-get update时返回大量404 Not Found错误，容器网络连通性正常（可ping通google.com）。

apt-get update错误日志 #

# apt-get update
Ign http://security.debian.org jessie/updates InRelease
Ign http://security.debian.org jessie/updates Release.gpg
Ign http://httpredir.debian.org jessie InRelease
Ign http://security.debian.org jessie/updates Release
Ign http://httpredir.debian.org jessie-updates InRelease
Err http://security.debian.org jessie/updates/main amd64 Packages

Ign http://httpredir.debian.org jessie Release.gpg
Ign http://httpredir.debian.org jessie-updates Release.gpg
Err http://security.debian.org jessie/updates/main amd64 Packages

Ign http://httpredir.debian.org jessie Release
Err http://security.debian.org jessie/updates/main amd64 Packages

Ign http://httpredir.debian.org jessie-updates Release
Err http://security.debian.org jessie/updates/main amd64 Packages

Err http://security.debian.org jessie/updates/main amd64 Packages
  404  Not Found [IP: 151.101.130.132 80]
Err http://httpredir.debian.org jessie/main amd64 Packages
  404  Not Found
Err http://httpredir.debian.org jessie-updates/main amd64 Packages
  404  Not Found
W: Failed to fetch http://security.debian.org/dists/jessie/updates/main/binary-amd64/Packages  404  Not Found [IP: 151.101.130.132 80]

W: Failed to fetch http://httpredir.debian.org/debian/dists/jessie/main/binary-amd64/Packages  404  Not Found

W: Failed to fetch http://httpredir.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages  404  Not Found       

E: Some index files failed to download. They have been ignored, or old ones used instead.

网络连通性测试结果 #

# ping google.com
PING google.com (142.250.187.206): 56 data bytes
64 bytes from 142.250.187.206: icmp_seq=0 ttl=37 time=58.393 ms
64 bytes from 142.250.187.206: icmp_seq=1 ttl=37 time=22.499 ms
64 bytes from 142.250.187.206: icmp_seq=2 ttl=37 time=21.658 ms
...

• Debian Jessie已停止官方支持：Debian 8（Jessie）在2020年6月结束长期支持，官方软件源httpredir.debian.org和security.debian.org已移除该版本的软件包索引，导致请求返回404。
• 镜像依赖的系统和软件版本过旧：php:5.5.38-apache基于Debian Jessie构建，而PHP 5.5本身也早已停止维护，镜像内默认配置的软件源指向已下线的官方地址。

内容的提问来源于stack exchange，提问作者Martyn