Open Stack

Hi all,

So I wanted to start some discussion on $subject, because atm we have a
couple of patches adding support for new services (which is great!):

Manila: https://review.openstack.org/#/c/188137/
Sahara: https://review.openstack.org/#/c/220863/

So, firstly I am *not* aiming to be any impediment to those landing, and I
know they have been in-progress for some time.  These look pretty close to
being ready to land and overall I think new service integration is a very
good thing for TripleO.

However, given the recent evolution towards the "big tent" of OpenStack, I
wanted to get some ideas on what an effective way to selectively enable
services would look like, as I can imagine not all users of TripleO want to
deploy all-the-services all of the time.

I was initially thinking we simply have e.g "EnableSahara" as a boolean in
overcloud-without-mergepy, and wire that in to the puppet manifests, such
that the services are not configured/started.  However comments in the
Sahara patch indicate it may be more complex than that, in particular
requiring changes to the loadbalancer puppet code and os-cloud-config.

This is all part of the more general "composable roles" problem, but is
there an initial step we can take, which will make it easy to simply
disable services (and ideally not pay the cost of configuring them at all)
on deployment?

Interested in peoples thoughts on this - has anyone already looked into it,
or is there any existing pattern we can reuse?

As mentioned above, not aiming to block anything on this, I guess we can
figure it out and retro-fit it to whatever services folks want to
selectively disable later if needed.

Thanks,

Steve