A few thoughts on this, firstly you are right to an extent - Docker doesn't give you portability completely due to binary dependencies, but if for example I wanted to move my app from the same major version of CentOS or RHEL on a virtual machine to something running with the same major version in the cloud it should be relatively straightforward. You are right though that this won't work going from something like Ubuntu to Suse for example.
The key bit is that we are starting to converge on a standard container for the Linux OS and with Red Hat working to get things working with SELinux we should have a pretty awesome container for our apps.
Given the above I'd rather standardise on an Open project that adds a lot more value to LXC and hides that complexity away and given the largest linux vendor is putting it's weight behind this I'd say this is rather awesome!
<title>SELinux context</title>
<para>
If lxc was compiled and installed with SELinux support, and the host
system has SELinux enabled, then the SELinux context under which the
container should be run can be specified in the container
configuration. The default is <command>unconfined_t</command>,
which means that lxc will not attempt to change contexts.
</para>
Additionally, LXC is "Open" since it is GPL2, it has been around since before 2006 so it's as much a de-facto standard as you can get, it's already supported by multiple other projects and distros, and it doesn't lock you into "the Docker way" of doing things - you get to choose how you implement it. It's flexible, lightweight, simple, and stable. Docker will work for many use cases, but LXC will work for all of them. It's lynx vs wget, basically.
The libvirt-sandbox project looks like a nice way to manage sandboxed selinux-supported lxc instances that you can convert to qemu/kvm depending on your needs.
LXC currently has a gaping hole around security because it doesn't use SELinux - you might want to read this article: http://mattoncloud.org/2012/07/16/are-lxc-containers-enough/
The key bit is that we are starting to converge on a standard container for the Linux OS and with Red Hat working to get things working with SELinux we should have a pretty awesome container for our apps.
Finally, Docker adds a lot more on top of LXC, which is why people love it so much - you can see a comprehensive answer by Solomon Hykes here: http://stackoverflow.com/questions/17989306/what-does-docker...
Given the above I'd rather standardise on an Open project that adds a lot more value to LXC and hides that complexity away and given the largest linux vendor is putting it's weight behind this I'd say this is rather awesome!