Application virtualization is not easy. Docker has done an amazing job of marketing the benefits, but the long-term solution is that OS and application developers (not sysadmins) will design minimal OS+app bundles. See recent discussion on Microsoft research, https://news.ycombinator.com/item?id=8257250
Docker+CoreOS mimics Google infrastructure - CoreOS is probably a better "minimal server OS" choice for Docker than Ubuntu.
I totally agree about both statements. My next hands on and post on that topic will be about moving from Ubuntu to CoreOS and what it implies for our existing infrastructure (I'm the article author)
We need a cross-distro dependency manager that can generate app-liance images for baremetal, lxc, kvm, aws/xen, vmware, azure/hyperv, illumos/bsd/zones, etc. Such a dependency manager could encode management-related policy (e.g. networking) into an image manifest that could be parsed by deployment tools. As an image format, OVF was ratified by DMTF and may have useful concepts, http://en.wikipedia.org/wiki/Open_Virtualization_Format
Docker+CoreOS mimics Google infrastructure - CoreOS is probably a better "minimal server OS" choice for Docker than Ubuntu.