apt-cacher-ng

This is pretty hacky, but it works well enough.

Set up rawdns to be the default DNS for all your containers.

Run something like:

$ docker run -d --name apt-cacher-ng --dns 8.8.8.8 --dns 8.8.4.4 tianon/apt-cacher-ng

Add the following to your config.json for rawdns:

	"http.debian.net.": {
		"type": "static",
		"cnames": [ "apt-cacher-ng.docker" ],
		"nameservers": [ "127.0.0.1" ]
	},
	"archive.ubuntu.com.": {
		"type": "static",
		"cnames": [ "apt-cacher-ng.docker" ],
		"nameservers": [ "127.0.0.1" ]
	},

Presto: all containers magically use your machine-local apt-cacher-ng instance instead of the public mirrors.