这是我出现的问题

root@40b82f229080:~# apt-get update 
Err:1 http://deb.debian.org/debian buster InRelease                  Temporary failure resolving 'deb.debian.org'
Err:2 http://security.debian.org/debian-security buster/updates InReleaseTemporary failure resolving 'security.debian.org'
Err:3 http://deb.debian.org/debian buster-updates InRelease          Temporary failure resolving 'deb.debian.org'
Reading package lists... Done    
W: Failed to fetch http://deb.debian.org/debian/dists/buster/InRelease  Temporary failure resolving 'deb.debian.org'
W: Failed to fetch http://security.debian.org/debian-security/dists/buster/updates/InRelease  Temporary failure resolving 'security.debian.org'
W: Failed to fetch http://deb.debian.org/debian/dists/buster-updates/InRelease  Temporary failure resolving 'deb.debian.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.

出现这个问题，大概率是DNS解析的问题，需要指定下dns

vim /etc/docker/daemon.json
{"dns": ["114.114.114.114","8.8.8.8"]
}