On Tue, Jan 9, 2024, at 18:56, Proven Provenzano wrote: > Hi folks, > > Thank you for the questions. > > Let me clarify about reorder first. The reorder of unstable metadata > versions should be infrequent.
Why does it need to be infrequent? We should be able to reorder unstable metadata versions as often as we like. There are no guarantees about unstable MVs. > The time you reorder is when a feature that > requires a higher metadata version to enable becomes "production ready" and > the features with unstable metadata versions less than the new stable one > are moved to metadata versions greater than the new stable feature. When we > reorder, we are always allocating a new MV and we are never reusing an > existing MV even if it was also unstable. This way a developer upgrading > their environment with a specific unstable MV might see existing > functionality stop working but they won't see new MV dependent > functionality magically appear. The feature set for a given unstable MV > version can only decrease with reordering. If you use an unstable MV, you probably won't be able to upgrade your software. Because whenever something changes, you'll probably get serialization exceptions being thrown inside the controller. Fatal ones. Given that this is true, there's no reason to have special rules about what we can and can't do with unstable MVs. We can do anything. > > How do we define "production ready" and when should we bump > LATEST_PRODUCTION? I would like to define it to be the point where the > feature is code complete with tests and the KIP for it is approved. However > even with this definition if the feature later develops a major issue it > could still block future features until the issue is fixed which is what we > are trying to avoid here. We could be much more formal about this and let > the release manager for a release define what is stable for a given release > and then do the bump just after the branch is created on the branch. When > an RC candidate is accepted, the bump would be backported. I would like to > hear other ideas here. > Yeah, it's an interesting question. Overall, I think developers should define when a feature is production ready. The question to ask is, "are you ready to take this feature to production in your workplace?" I think most developers do have a sense of this. Obviously bugs and mistakes can happen, but I think this standard would avoid most of the issues that we're trying to avoid by having unstable MVs in the first place. ELR is a good example. Nobody would have said that it was production ready in 3.7 ... hence it belonged (and still belongs) in an unstable MV, until that changes (hopefully soon :) ) best, Colin > --Proven > > On Tue, Jan 9, 2024 at 3:26 PM Colin McCabe <cmcc...@apache.org> wrote: > >> Hi Justine, >> >> Yes, this is an important point to clarify. Proven can comment more, but >> my understanding is that we can do anything to unstable metadata versions. >> Reorder them, delete them, change them in any other way. There are no >> stability guarantees. If the current text is unclear let's add more >> examples of what we can do (which is anything) :) >> >> best, >> Colin >> >> >> On Mon, Jan 8, 2024, at 14:18, Justine Olshan wrote: >> > Hey Colin, >> > >> > I had some offline discussions with Proven previously and it seems like >> he >> > said something different so I'm glad I brought it up here. >> > >> > Let's clarify if we are ok with reordering unstable metadata versions :) >> > >> > Justine >> > >> > On Mon, Jan 8, 2024 at 1:56 PM Colin McCabe <cmcc...@apache.org> wrote: >> > >> >> On Mon, Jan 8, 2024, at 13:19, Justine Olshan wrote: >> >> > Hey all, >> >> > >> >> > I was wondering how often we plan to update LATEST_PRODUCTION metadata >> >> > version. Is this something we should do as soon as the feature is >> >> complete >> >> > or something we do when we are releasing kafka. When is the time we >> >> abandon >> >> > a MV so that other features can be unblocked? >> >> >> >> Hi Justine, >> >> >> >> Thanks for reviewing. >> >> >> >> The idea is that you should bump LATEST_PRODUCTION when you want to >> take a >> >> feature to production. That could mean deploying it internally >> somewhere to >> >> production, or doing an Apache release that lets everyone deploy the >> thing >> >> to production. >> >> >> >> Not in production? No need to care about this. Make any changes you >> like. >> >> >> >> As a corollary, we should keep the LATEST_PRODUCTION version as low as >> it >> >> can be. If you haven't tested the feature, don't freeze it in stone yet. >> >> >> >> > >> >> > I am just considering a feature that may end up missing a release. It >> >> seems >> >> > like maybe that MV would block future metadata versions until we >> decide >> >> the >> >> > feature won't make the cut. From that point, all "ready" features >> should >> >> be >> >> > able to be released. >> >> >> >> The intention is the opposite. A feature in an unstable metadata version >> >> doesn't block anything. You can always move a feature from one unstable >> >> metadata version to another if the feature starts taking too long to >> finish. >> >> >> >> > I'm also wondering if the KIP should include some information about >> how a >> >> > metadata should be abandoned. Maybe there is a specific message to >> write >> >> in >> >> > the file? So folks who were maybe waiting on that version know they >> can >> >> > release their feature? >> >> > >> >> > I am also assuming that we don't shift all the waiting metadata >> versions >> >> > when we abandon a version, but it would be good to clarify and >> include in >> >> > the KIP. >> >> >> >> I'm not sure what you mean by abandoning a version. We never abandon a >> >> version once it's stable. >> >> >> >> Unstable versions can change. I wouldn't describe this as "abandonment", >> >> just the MV changing prior to release. >> >> >> >> In a similar way, the contents of the 3.7 branch will change up until >> >> 3.7.0 is released. Once it gets released, it's never unreleased. We just >> >> move on to 3.7.1. Same thing here. >> >> >> >> best, >> >> Colin >> >> >> >> > >> >> > Thanks, >> >> > >> >> > Justine >> >> > >> >> > On Mon, Jan 8, 2024 at 12:44 PM Colin McCabe <cmcc...@apache.org> >> wrote: >> >> > >> >> >> Hi Proven, >> >> >> >> >> >> Thanks for the KIP. I think there is a need for this capability, for >> >> those >> >> >> of us who deploy from trunk (or branches dervied from trunk). >> >> >> >> >> >> With regard to "unstable.metadata.versions.enable": is this going to >> be >> >> a >> >> >> documented configuration, or an internal one? I am guessing we want >> it >> >> to >> >> >> be documented, so that users can use it. If we do, we should probably >> >> also >> >> >> very prominently warn that THIS WILL BREAK UPGRADES FOR YOUR CLUSTER. >> >> That >> >> >> includes logging an ERROR message on startup, etc. >> >> >> >> >> >> It would be good to document if a release can go out that contains >> >> "future >> >> >> MVs" that are unstable. Like can we make a 3.8 release that contains >> >> >> IBP_4_0_IV0 in MetadataVersion.java, as an unstable future MV? >> >> Personally I >> >> >> think the answer should be "yes," but with the usual caveats. When >> the >> >> >> actual 4.0 comes out, the unstable 4.0 MV that shipped in 3.8 >> probably >> >> >> won't work, and you won't be able to upgrade. (It was unstable, we >> told >> >> you >> >> >> not to use it.) >> >> >> >> >> >> best, >> >> >> Colin >> >> >> >> >> >> >> >> >> On Fri, Jan 5, 2024, at 07:32, Proven Provenzano wrote: >> >> >> > Hey folks, >> >> >> > >> >> >> > I am starting a discussion thread for managing unstable metadata >> >> >> > versions >> >> >> > in Apache Kafka. >> >> >> > >> >> >> >> >> >> https://cwiki.apache.org/confluence/display/KAFKA/KIP-1014%3A+Managing+Unstable+Metadata+Versions+in+Apache+Kafka >> >> >> > >> >> >> > This KIP is actually already implemented in 3.7 with PR >> >> >> > https://github.com/apache/kafka/pull/14860. >> >> >> > I have created this KIP to explain the motivation and how managing >> >> >> Metadata >> >> >> > Versions is expected to work. >> >> >> > Comments are greatly appreciated as this process can always be >> >> improved. >> >> >> > >> >> >> > -- >> >> >> > --Proven >> >> >> >> >> >>
