lxc-create wastes disk space by keeping installation debs

A default ubuntu container created using "lxc-create -n ubuntu -t ubuntu" results in 386M space used on /var/lib/lxc/ubuntu/rootfs. A big part of that space is used by cached debs on /var/lib/lxc/ubuntu/rootfs/var/cache/apt/archives/ . Running "apt-get clean" inside the container's rootfs reduced space usage to 242M.

The wasted space becomes even more apparent if the backing store supports compression (e.g. zfsonlinux with gzip compression enabled). In this case the original used space (after compression) was 196M, and was reduced to 95M after the cached package files are removed, over 50% disk space saving.

Suggestion: Modify lxc-ubuntu template to run "apt-get clean" inside the container's rootfs as part of container creation process.

# lsb_release -rd
Description: Ubuntu 12.04.1 LTS
Release: 12.04

# apt-cache policy lxc
lxc:
  Installed: 0.7.5-3ubuntu62
  Candidate: 0.7.5-3ubuntu62
  Version table:
 *** 0.7.5-3ubuntu62 0
        500 http://archive.ubuntu.com/ubuntu/ precise-updates/universe amd64 Packages
        100 /var/lib/dpkg/status
     0.7.5-3ubuntu52 0
        500 http://archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages

Expected result:
"lxc-create -t ubuntu" result in a container which uses disk space efficiently

Actual result:
"lxc-create -t ubuntu" result in a container which uses more disk space than it should