Open Stack

Let's for a minute imagine that each of the raised concerns is 
addressable. And as a thought experiment, let's put here WHAT has to be 
addressed for Kolla w/o the need of abandoning it for a custom tooling:

On 03.05.2020 21:26, Alex Schultz wrote:
> On Sat, May 2, 2020 at 7:45 AM Jeremy Stanley <fungi at yuggoth.org> wrote:
>>
>> On 2020-05-01 15:18:13 -0500 (-0500), Kevin Carter wrote:
>>> As you may have seen, the TripleO project has been testing the
>>> idea of building container images using a simplified toolchain
>> [...]
>>
>> Is there an opportunity to collaborate around the proposed plan for
>> publishing basic docker-image-based packages for OpenStack services?
>>
>>      https://review.opendev.org/720107
>>
>> Obviously you're aiming at solving this for a comprehensive
>> deployment rather than at a packaging level, just wondering if
>> there's a way to avoid having an explosion of different images for
>> the same services if they could ultimately use the same building
>> blocks. (A cynical part of me worries that distro "party lines" will
>> divide folks on what the source of underlying files going into
>> container images should be, but I'm sure our community is better
>> than that, after all we're all in this together.)
>>
> 
> I think this assumes we want an all-in-one system to provide
> containers. And we don't.  That I think is the missing piece that
> folks don't understand about containers and what we actually need.
> 
> I believe the issue is that the overall process to go from zero to an
> application in the container is something like the following:
> 
> 1) input image (centos/ubi0/ubuntu/clear/whatever)

* support ubi8 base images

> 2) Packaging method for the application (source/rpm/dpkg/magic)

* abstract away all the packaging methods (at least above the base 
image) to some (better?) DSL perhaps

> 3) dependencies provided depending on item #1 & 2
> (venv/rpm/dpkg/RDO/ubuntu-cloud/custom)

* abstract away all the dependencies (atm I can only think of go.mod & 
Go's vendor packages example, sorry) to some extra DSL & CLI tooling may be

> 4) layer dependency declaration (base -> nova-base -> nova-api,
> nova-compute, etc)

* is already fully covered above, I suppose

> 5) How configurations are provided to the application (at run time or at build)

(what is missing for the run time, almost a perfection yet?)
* for the build time, is already fully covered above, i.e. extra DSL & 
CLI tooling (my biased example: go mod tidy?)

> 6) How application is invoked when container is ultimately launched
> (via docker/podman/k8s/etc)

* have a better DSL to abstract away all the container runtime & 
orchestration details beneath

> 7) Container build method (docker/buildah/other)

* support for buildah (more fancy abstractions and DSL extenstions ofc!)

> 
> The answer to each one of these is dependent on the expectations of
> the user or application consuming these containers.  Additionally this
> has to be declared for each dependent application as well
> (rabbitmq/mariadb/etc). Kolla has provided this at a complexity cost
> because it needs to support any number of combinations for each of

* have better modularity: offload some of the "combinations" to 
interested 3rd party maintainers (split repos into pluggable modules) 
and their own CI/CD.

> these.  Today TripleO doesn't use the build method provided by Kolla
> anymore because we no longer support docker.  This means we only use
> Kolla to generate Dockerfiles as inputs to other processes. It should

NOTE: there is also kolla startup/config APIs on which TripleO will 
*have to* rely for the next 3-5 years or so. Its compatibility shall not 
be violated.

> be noted that we also only want Dockerfiles for the downstream because
> they get rebuilt with yet another different process. So for us, we
> don't want the container and we want a method for generating the
> contents of the container.

* and again, have better pluggability to abstract away all the 
downstream vs upstream specifics (btw, I'm not bought on the new custom 
tooling can solve this problem in a different way but still using 
better/simpler DSL & tooling)

> 
> IMHO containers are just glorified packaging (yet again and one that
> lacks ways of expressing dependencies which is really not beneficial
> for OpenStack).  I do not believe you can or should try to unify the
> entire container declaration and building into a single application.
> You could rally around a few different sets of tooling that could
> provide you the pieces for consumption. e.g. A container file
> templating engine, a building engine, and a way of
> expressing/consuming configuration+execution information.
> 
> I applaud the desire to try and unify all the things, but as we've

So the final call: have pluggable and modular design, adjust DSL and 
tooling to meet those goals for Kolla. So that one who doesn't chase for 
unification, just sets up his own module and plugs it into build 
pipeline. Hint: that "new simpler tooling for TripleO" may be that 
pluggable module!

> seen time and time again when it comes to deployment, configuration
> and use cases. Trying to solve for all the things ends up having a
> negative effect on the UX because of the complexity required to handle
> all the cases (look at tripleo for crying out loud).  I believe it's
> time to stop trying to solve all the things with a giant hammer and
> work on a bunch of smaller nails and let folks construct their own
> hammer.
> 
> Thanks,
> -Alex
> 
> 
> 
> 
>> Either way, if they can both make use of the same speculative
>> container building workflow pioneered in Zuul/OpenDev, that seems
>> like a huge win (and I gather the Kolla "krew" are considering
>> redoing their CI jobs along those same lines as well).
>> --
>> Jeremy Stanley
> 
> 


-- 
Best regards,
Bogdan Dobrelya,
Irc #bogdando