Open Stack

On 10/17/2013 09:06 PM, Sam Alba wrote:
> Hi all,
> 
> I've been recently working on a Docker plugin for Heat that makes it
> possible to use Docker containers as resources.
> 
> I've just opened the repository:
> https://github.com/dotcloud/openstack-heat-docker
> 
> It's now possible to do that via Nova (since there is now a Docker
> driver for it). But the idea here is not to replace the Nova driver
> with this Heat plugin, the idea is just to propose a different path.
> 
> Basically, Docker itself has a Rest API[1] with all features needed to
> deploy and manage containers, the Nova driver uses this API. However
> having the Nova API in front of it makes it hard to bring all Docker
> features to the user, basically everything has to fit into the Nova
> API. For instance, docker commit/push are mapped to nova snapshots,
> etc... And a lot of Docker features are not available yet; I admit
> that some of them will be hard to support (docker Env variables,
> Volumes, etc... how should they fit in Nova?).

But we haven't talked about any of this yet, have we?  :-)

> The idea of this Docker plugin for Heat is to use the whole Docker API
> directly from a template. All possible parameters for creating a
> container from the Docker API[2] can be defined from the template.
> This allows more flexibility.
> 
> Since this approach is a bit different from the normal OpenStack
> workflow (for instance, Nova's role is to abstract all computing units
> right now), I am interested to get feedback on this.
> 
> Obviously, I'll keep maintaining the Docker driver for Nova and I'm
> also working on putting together some new features I'll propose for
> the next release.
> 
> 
> [1] http://docs.docker.io/en/latest/api/docker_remote_api_v1.5/
> [2] http://docs.docker.io/en/latest/api/docker_remote_api_v1.5/#create-a-container
> 

The way Nova uses the docker API is that each nova-compute service is
managing docker locally.  So, Nova allows you to utilize docker through
a single API across many nodes, right?  How does this work with this plugin?

I think my biggest piece of feedback is that I would like to talk about
how we can evolve Nova to better support containers instead of just
assuming it's hard and that another direction has to be taken.  It could
be that the combination of some Nova enhancements and some
docker-specific Heat features makes sense.  I don't know yet.  Can we
get into some more details about what drove you to think you needed to
bypass Nova?

-- 
Russell Bryant