[openstack-dev] [TripleO] Next steps for pre-deployment workflows (e.g derive parameters)

James Slagle james.slagle at gmail.com
Wed Nov 8 22:55:01 UTC 2017

On Wed, Nov 8, 2017 at 7:16 AM, James Slagle <james.slagle at gmail.com> wrote:
> On Wed, Nov 8, 2017 at 12:09 AM, Steven Hardy <shardy at redhat.com> wrote:
>> Hi all,
>> Today I had a productive hallway discussion with jtomasek and
>> stevebaker re $subject, so I wanted to elaborate here for the benefit
>> of those folks not present.  Hopefully we can get feedback on the
>> ideas and see if it makes sense to continue and work on some patches:
>> The problem under discussion is how do we run pre-deployment workflows
>> (such as those integrated recently to calculate derived parameters,
>> and in future perhaps also those which download container images etc),
>> and in particular how do we make these discoverable via the UI
>> (including any input parameters).

After chatting with jtomasek on irc, I wanted to clarify that the part
of this proposal I'm hesitant about.

Specifically, it's adding an interface for any service to specify a
mistral workflow, that in theory could do anything, as part of a
pre_deploy interface "contract". If we do offer such an interface, I
think it ought to be driven via ansible tasks/plays that are available
as Heat stack outputs to match the config-download pattern.

Perhaps for just deriving parameters, having a way to specify
workflows for the UI is Ok. It's more of the generic interface I'm not
so keen on. As it relates to your example of downloading container
images, it seems we could have a generic ansible task to do that, that
could then be executed with Mistral for API purposes instead of
specifying the Mistral workflow directly in the templates/roles_data.

-- James Slagle

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