[Rdo-list] packstack future

[Steven Hardy]

Hi Tim,

On Sun, Sep 06, 2015 at 07:35:30AM +0000, Tim Bell wrote:
>    Reading the RDO September newsletter, I noticed a mail thread
>    (https://www.redhat.com/archives/rdo-list/2015-August/msg00032.html) on
>    the future of packstack vs rdo-manager.
> 
>    We use packstack to spin up small OpenStack instances for development and
>    testing. Typical cases are to have a look at the features of the latest
>    releases or do some prototyping of an option we've not tried yet.
> 
>    It was not clear to me based on the mailing list thread as to how this
>    could be done using rdo-manager unless you already have the undercloud
>    configiured by RDO.

>    Has there been any further discussions around packstack future ?

Thanks for raising this - I am aware that a number of folks have been
thinking about this topic (myself included), but I don't think we've yet
reached a definitive consensus re the path forward yet.

Here's my view on the subject:

1. Packstack is clearly successful, useful to a lot of folks, and does
satisfy a use-case currently not well served via rdo-manager, so IMO we
absolutely should maintain it until that is no longer the case.

2. Many people are interested in easier ways to stand up PoC environments
via rdo-manager, so we do need to work on ways to make that easier (or even
possible at all in the single-node case).

3. It would be really great if we could figure out (2) in such a way as to
enable a simple migration path from packstack to whatever the PoC mode of
rdo-manager ends up being, for example perhaps we could have an rdo manager
interface which is capable of consuming a packstack answer file?

Re the thread you reference, it raises a number of interesting questions,
particularly the similarities/differences between an all-in-one packstack
install and an all-in-one undercloud install;

>From an abstract perspective, installing an all-in-one undercloud looks a
lot like installing an all-in-one packstack environment, both sets of tools
take a config file, and create a puppet-configured all-in-one OpenStack.

But there's a lot of potential complexity related to providing a
flexible/configurable deployment (like packstack) vs an opinionated
bootstrap environment (e.g the current instack undercloud environment).

There are a few possible approaches:

- Do the work to enable a more flexibly configured undercloud, and just
  have that as the "all in one" solution

- Have some sort of transient undercloud (I'm thinking a container) which
  exists only for the duration of deploying the all-in-one overcloud, on
  the local (pre-provisioned, e.g not via Ironic) host.  Some prototyping
  of this approach has already happened [1] which I think James Slagle has
  used to successfully deploy TripleO templates on pre-provisioned nodes.

The latter approach is quite interesting, because it potentially maintains
a greater degree of symmetry between the minimal PoC install and real
production deployments (e.g you'd use the same heat templates etc), it
could also potentially provide easier access to features as they are added
to overcloud templates (container integration, as an example), vs
integrating new features in two places.

Overall at this point I think there are still many unanswered questions
around enabling the PoC use-case for rdo-manager (and, more generally
making TripleO upstream more easily consumable for these kinds of
use-cases).  I hope/expect we'll have a TripleO session on this at the
forthcoming summit, where we refine the various ideas people have been
investigating, and define the path forward wrt PoC deployments.

Hopefully that is somewhat helpful, and thanks again for re-starting this
discussion! :)

Steve

[1] https://etherpad.openstack.org/p/noop-softwareconfig