[TC][PTL][ops][all] Release cadence, deprecation, and testing

Mark Goddard mark at stackhpc.com
Thu Mar 10 09:01:44 UTC 2022

On Wed, 9 Mar 2022 at 22:35, Dan Smith <dms at danplanet.com> wrote:
> Hi all,
> As you probably already know from gmann's reporting, the TC recently
> passed a resolution[1] regarding the release cadence. This, in response
> to some discussion around moving to different release cycle lengths,
> becomes mostly a change regarding our deprecation procedures, as well as
> a call to support the ability to skip certain releases (designated
> "tock" releases) while sticking on a yearly cycle (designated "tick"
> releases).
> In support of the goal of moving to this new cadence for the AA release
> (i.e. the yet unnamed release to come after Zed), I have introduced[2] a
> new grenade-skip-level job, which tests skipping "tock" releases and
> going straight from one tick to the following. We intend this to be a
> voting job in AA, making sure it works from Yoga->AA. Right now it tests
> Wallaby->Yoga for informational purposes. We would recommend projects
> enable that as voting, or define their own job to do similar testing as
> soon as possible. Manila has already started[3] this. Note that existing
> grenade testing between each adjacent release remains unchanged in this
> scheme.
> On the topic of deprecation, we moved the current definition of
> deprecation procedures from the soon-to-be-removed tag definition to a
> new document in project-team-guide[4]. This now describes the procedures
> in terms of the tick-tock release arrangement, and is worth a read.
> As the PTG is coming up, we will certainly discuss this topic in the PTL
> Interaction[5] session. It would also be advisable to discuss the
> project-specific details of this in the various project sessions. By
> identifying this plan early and setting our goals for AA, we have a good
> amount of time between now and then to get our heads wrapped around what
> (if any) things we need to be doing. Luckily, the introduction of the
> job to test this from wallaby to yoga required almost no project changes
> to get working, which is a good indicator that it won't be too laborious
> for most projects to adopt.
> --Dan
> 1: https://governance.openstack.org/tc/resolutions/20220210-release-cadence-adjustment.html
> 2: https://review.opendev.org/c/openstack/grenade/+/826101
> 3: https://review.opendev.org/c/openstack/manila/+/830277
> 4: https://docs.openstack.org/project-team-guide/deprecation.html
> 5: https://etherpad.opendev.org/p/tc-ptl-interaction-zed

Thanks for writing this up, Dan. Overall it seems sensible. One thing
that jumps out from the TC resolution is this:

"This scheme does not necessarily dictate that live or rolling
upgrades need to be supported between tick releases. Meaning RPC
compatibility between N to N-1 guarantees can remain, resulting in
deployments that are on a tick-tick release schedule requiring some
downtime during an upgrade because components will be spanning more
than two actual releases."

>From the perspective of deployment tools, this would mean needing to
support two different upgrade strategies. Given the constraints around
DB migrations, would it be too much effort for projects to also
support N-2 to N RPC compatibility?


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