Hi, Colin, Thanks for the update. Since the PR also introduces a new version of BrokerRegistrationRequest, could we include that change in the KIP update too?
Jun On Mon, Jul 8, 2024 at 11:08 AM Colin McCabe <cmcc...@apache.org> wrote: > Hi all, > > I've updated the approach in https://github.com/apache/kafka/pull/16421 > so that we change the minVersion=0 to minVersion=1 in older > ApiVersionsResponses. > > I hope we can get this in soon and unblock the features that are waiting > for it! > > best, > Colin > > On Wed, Jul 3, 2024, at 10:55, Jun Rao wrote: > > Hi, David, > > > > Thanks for the reply. In the common case, there is no difference between > > omitting just v0 of the feature or omitting the feature completely. It's > > just when an old client is used, there is some difference. To me, > > omitting just v0 of the feature seems slightly better for the old client. > > > > Jun > > > > On Wed, Jul 3, 2024 at 9:45 AM David Jacot <dja...@confluent.io.invalid> > > wrote: > > > >> Hi Jun, Colin, > >> > >> Thanks for your replies. > >> > >> If the FeatureCommand relies on version 0 too, my suggestion does not > work. > >> Omitting the features for old clients as suggested by Colin seems fine > for > >> me. In practice, administrators will usually use a version of > >> FeatureCommand matching the cluster version so the impact is not too bad > >> knowing that the first features will be introduced from 3.9 on. > >> > >> Best, > >> David > >> > >> On Tue, Jul 2, 2024 at 2:15 AM Colin McCabe <cmcc...@apache.org> wrote: > >> > >> > Hi David, > >> > > >> > In the ApiVersionsResponse, we really don't have an easy way of > mapping > >> > finalizedVersion = 1 to "off" in older releases such as 3.7.0. For > >> example, > >> > if a 3.9.0 broker advertises that it has finalized group.version = 1, > >> that > >> > will be treated by 3.7.0 as a brand new feature, not as "KIP-848 is > off." > >> > However, I suppose we could work around this by not setting a > >> > finalizedVersion at all for group.version (or any other feature) if > its > >> > finalized level was 1. We could also work around the "deletion = set > to > >> 0" > >> > issue on the server side. The server can translate requests to set the > >> > finalized level to 0, into requests to set it to 1. > >> > > >> > So maybe this solution is worth considering, although it's > unfortunate to > >> > lose 0. I suppose we'd have to special case metadata.version being > set to > >> > 1, since that was NOT equivalent to it being "off" > >> > > >> > best, > >> > Colin > >> > > >> > > >> > On Mon, Jul 1, 2024, at 10:11, Jun Rao wrote: > >> > > Hi, David, > >> > > > >> > > Yes, that's another option. It probably has its own challenges. For > >> > > example, the FeatureCommand tool currently treats disabling a > feature > >> as > >> > > setting the version to 0. It would be useful to get Jose's opinion > on > >> > this > >> > > since he introduced version 0 in the kraft.version feature. > >> > > > >> > > Thanks, > >> > > > >> > > Jun > >> > > > >> > > On Sun, Jun 30, 2024 at 11:48 PM David Jacot > >> <dja...@confluent.io.invalid > >> > > > >> > > wrote: > >> > > > >> > >> Hi Jun, Colin, > >> > >> > >> > >> Have we considered sticking with the range going from version 1 to > N > >> > where > >> > >> version 1 would be the equivalent of "disabled"? In the > group.version > >> > case, > >> > >> we could introduce group.version=1 that does basically nothing and > >> > >> group.version=2 that enables the new protocol. I suppose that we > could > >> > do > >> > >> the same for the other features. I agree that it is less elegant > but > >> it > >> > >> would avoid all the backward compatibility issues. > >> > >> > >> > >> Best, > >> > >> David > >> > >> > >> > >> On Fri, Jun 28, 2024 at 6:02 PM Jun Rao <j...@confluent.io.invalid> > >> > wrote: > >> > >> > >> > >> > Hi, Colin, > >> > >> > > >> > >> > Yes, #3 is the scenario that I was thinking about. > >> > >> > > >> > >> > In either approach, there will be some information missing in the > >> old > >> > >> > client. It seems that we should just pick the one that's less > wrong. > >> > In > >> > >> the > >> > >> > more common case when a feature is finalized on the server, > >> > presenting a > >> > >> > supported feature with a range of 1-1 seems less wrong than > omitting > >> > it > >> > >> in > >> > >> > the output of "kafka-features describe". > >> > >> > > >> > >> > Thanks, > >> > >> > > >> > >> > Jun > >> > >> > > >> > >> > On Thu, Jun 27, 2024 at 9:52 PM Colin McCabe <cmcc...@apache.org > > > >> > wrote: > >> > >> > > >> > >> > > Hi Jun, > >> > >> > > > >> > >> > > This is a fair question. I think there's a few different > scenarios > >> > to > >> > >> > > consider: > >> > >> > > > >> > >> > > 1. mixed server software versions in a single cluster > >> > >> > > > >> > >> > > 2. new client software + old server software > >> > >> > > > >> > >> > > 3. old client software + new server software > >> > >> > > > >> > >> > > In scenario #1 and #2, we have old (pre-3.9) server software in > >> the > >> > >> mix. > >> > >> > > This old software won't support features like group.version and > >> > >> > > kraft.version. As we know, there are no features supported in > 3.8 > >> > and > >> > >> > older > >> > >> > > except metadata.version itself. So the fact that we leave out > some > >> > >> stuff > >> > >> > > from the ApiVersionResponse isn't terribly significant. We > weren't > >> > >> going > >> > >> > to > >> > >> > > be able to enable those post-3.8 features anyway, since > enabling a > >> > >> > feature > >> > >> > > requires ALL server nodes to support it. > >> > >> > > > >> > >> > > Scenario #3 is more interesting. With new server software, > >> features > >> > >> like > >> > >> > > group.version and kraft.version may be enabled. But due to the > >> > >> > KAFKA-17011 > >> > >> > > bug, we cannot accurately communicate the supported feature > range > >> > back > >> > >> to > >> > >> > > the old client. > >> > >> > > > >> > >> > > What is the impact of this? It depends on what the client is. > >> Today, > >> > >> the > >> > >> > > only client that cares about feature versions is admin client, > >> which > >> > >> can > >> > >> > > surface them through the Admin.describeFeatures API. So if we > omit > >> > the > >> > >> > > supported feature range, admi client won't report it. If we > fudge > >> > it by > >> > >> > > reporting it as 1-1 instead of 0-1, admin client will report > the > >> > fudged > >> > >> > > version. > >> > >> > > > >> > >> > > In theory, there could be other clients looking at the > supported > >> > >> feature > >> > >> > > ranges later, but I guess those will be post-3.8, if they ever > >> > exist, > >> > >> and > >> > >> > > so not subject to this problem. > >> > >> > > > >> > >> > > AdminClient returns a separate map for "supported features" and > >> > >> > "finalized > >> > >> > > features." So leaving out the supported versions for > group.version > >> > and > >> > >> > > kraft.version will not prevent the client from returning the > >> > finalized > >> > >> > > versions of those features to the old client. > >> > >> > > > >> > >> > > So basically we have a choice between missing information in > >> > >> > > Admin.describeFeatures and wrong information. I would lean > towards > >> > the > >> > >> > > missing information path, but I guess we should try out an old > >> > build of > >> > >> > > kafka-features.sh against a server with one of the new features > >> > >> enabled, > >> > >> > to > >> > >> > > make sure it looks the way we want. > >> > >> > > > >> > >> > > best, > >> > >> > > Colin > >> > >> > > > >> > >> > > > >> > >> > > On Thu, Jun 27, 2024, at 14:01, Jun Rao wrote: > >> > >> > > > Hi, Colin, > >> > >> > > > > >> > >> > > > ApiVersionResponse includes both supported and finalized > >> > features. If > >> > >> > we > >> > >> > > > only suppress features in the supported field, but not in the > >> > >> finalized > >> > >> > > > field, it can potentially lead to inconsistency in the older > >> > client. > >> > >> > For > >> > >> > > > example, if a future feature supporting V0 is finalized in > the > >> > >> broker, > >> > >> > an > >> > >> > > > old client issuing V3 of ApiVersionRequest will see the > feature > >> in > >> > >> the > >> > >> > > > finalized field, but not in the supported field. > >> > >> > > > > >> > >> > > > An alternative approach is to still include all features in > the > >> > >> > supported > >> > >> > > > field, but replace minVersion of 0 with 1. This may still > lead > >> to > >> > >> > > > inconsistency if a future feature is finalized at version 0. > >> > However, > >> > >> > > since > >> > >> > > > downgrading is less frequent than upgrading, this approach > seems > >> > >> > slightly > >> > >> > > > more consistent. > >> > >> > > > > >> > >> > > > No matter what approach we take, it would be useful to > document > >> > this > >> > >> > > > inconsistency to the old client. > >> > >> > > > > >> > >> > > > Thanks, > >> > >> > > > > >> > >> > > > Jun > >> > >> > > > > >> > >> > > > On Wed, Jun 26, 2024 at 1:18 PM Jun Rao <j...@confluent.io> > >> wrote: > >> > >> > > > > >> > >> > > >> Thanks for the reply, Justine and Colin. Sounds good to me. > >> > >> > > >> > >> > >> > > >> Jun > >> > >> > > >> > >> > >> > > >> On Wed, Jun 26, 2024 at 12:54 PM Colin McCabe < > >> > cmcc...@apache.org> > >> > >> > > wrote: > >> > >> > > >> > >> > >> > > >>> Hi Justine, > >> > >> > > >>> > >> > >> > > >>> Yes, that was what I was thinking. > >> > >> > > >>> > >> > >> > > >>> best, > >> > >> > > >>> Colin > >> > >> > > >>> > >> > >> > > >>> On Mon, Jun 24, 2024, at 11:11, Justine Olshan wrote: > >> > >> > > >>> > My understanding is that the tools that don't rely on > >> > ApiVersions > >> > >> > > should > >> > >> > > >>> > still return 0s when it is the correct value. I believe > >> these > >> > >> > > commands > >> > >> > > >>> do > >> > >> > > >>> > not require this API and thus can show 0 as versions. > >> > >> > > >>> > > >> > >> > > >>> > Likewise, when the old ApiVersionsRequest is used to > >> describe > >> > >> > > features, > >> > >> > > >>> we > >> > >> > > >>> > can't return 0 versions and we won't be able to see group > >> > version > >> > >> > > set. > >> > >> > > >>> > However, the new api will return 0 and the group version > >> > >> correctly. > >> > >> > > >>> > > >> > >> > > >>> > Let me know if this is consistent with your thoughts, > Colin. > >> > >> > > >>> > > >> > >> > > >>> > Justine > >> > >> > > >>> > > >> > >> > > >>> > On Mon, Jun 24, 2024 at 10:44 AM Jun Rao > >> > >> <j...@confluent.io.invalid > >> > >> > > > >> > >> > > >>> wrote: > >> > >> > > >>> > > >> > >> > > >>> >> Hi, Colin, > >> > >> > > >>> >> > >> > >> > > >>> >> Thanks for the update. The proposed change seems > reasonable > >> > to > >> > >> me. > >> > >> > > >>> Just one > >> > >> > > >>> >> clarification. > >> > >> > > >>> >> > >> > >> > > >>> >> The KIP can show version 0 of certain features with > >> > >> > version-mapping > >> > >> > > >>> >> and feature-dependencies. Will that part change? For > >> example, > >> > >> will > >> > >> > > the > >> > >> > > >>> tool > >> > >> > > >>> >> show version 0 features with --release-version 3.8 or > do we > >> > >> > exclude > >> > >> > > >>> them. > >> > >> > > >>> >> > >> > >> > > >>> >> bin/kafka-storage.sh version-mapping --release-version > >> > 3.6-IV1 > >> > >> > > >>> >> metadata.version=13 (3.6-IV1) transaction.version=0 > >> > >> > > >>> group.version=0 > >> > >> > > >>> >> kraft.version=0 > >> > >> > > >>> >> > >> > >> > > >>> >> Jun > >> > >> > > >>> >> > >> > >> > > >>> >> On Sat, Jun 22, 2024 at 2:19 PM José Armando García > Sancio > >> > >> > > >>> >> <jsan...@confluent.io.invalid> wrote: > >> > >> > > >>> >> > >> > >> > > >>> >> > Thanks for the update Colin. The changes make sense to > >> me. > >> > >> > > >>> >> > > >> > >> > > >>> >> > Are you planning to update the KIP to reflect this new > >> RPC > >> > >> > > version? > >> > >> > > >>> It > >> > >> > > >>> >> > would be good to document the semantics explained > above > >> in > >> > the > >> > >> > > KIP. > >> > >> > > >>> >> > > >> > >> > > >>> >> > Thanks! > >> > >> > > >>> >> > > >> > >> > > >>> >> > On Fri, Jun 21, 2024 at 8:22 PM Justine Olshan > >> > >> > > >>> >> > <jols...@confluent.io.invalid> wrote: > >> > >> > > >>> >> > > > >> > >> > > >>> >> > > Ok makes sense. I will update my PR. > >> > >> > > >>> >> > > > >> > >> > > >>> >> > > On Fri, Jun 21, 2024 at 5:09 PM Colin McCabe < > >> > >> > > cmcc...@apache.org> > >> > >> > > >>> >> wrote: > >> > >> > > >>> >> > > > >> > >> > > >>> >> > > > I think it's better to suppress the response in > v3. > >> The > >> > >> > issue > >> > >> > > >>> with > >> > >> > > >>> >> > > > modifying it is that there may be scenarios where > [1, > >> > 1] > >> > >> is > >> > >> > > the > >> > >> > > >>> >> actual > >> > >> > > >>> >> > > > supported range, and we'd want to know that. But > >> > leaving > >> > >> out > >> > >> > > the > >> > >> > > >>> >> > feature > >> > >> > > >>> >> > > > should be OK for older clients (it will be the > case > >> > with > >> > >> > > clients > >> > >> > > >>> old > >> > >> > > >>> >> > enough > >> > >> > > >>> >> > > > to send a v0, v1, or v2 ApiVersionsRequest anyway) > >> > >> > > >>> >> > > > > >> > >> > > >>> >> > > > best, > >> > >> > > >>> >> > > > Colin > >> > >> > > >>> >> > > > > >> > >> > > >>> >> > > > On Fri, Jun 21, 2024, at 16:46, Justine Olshan > wrote: > >> > >> > > >>> >> > > > > Thanks Colin, > >> > >> > > >>> >> > > > > > >> > >> > > >>> >> > > > > This makes sense to me. Namely in the case > where we > >> > >> > perhaps > >> > >> > > >>> don't > >> > >> > > >>> >> > want to > >> > >> > > >>> >> > > > > support version 0 anymore, we need the range to > be > >> > able > >> > >> to > >> > >> > > not > >> > >> > > >>> >> > include 0. > >> > >> > > >>> >> > > > > (In other words, we can't assume 0 is supported) > >> > >> > > >>> >> > > > > It is unfortunate that this change is a bit > tricky, > >> > but > >> > >> I > >> > >> > > think > >> > >> > > >>> >> it's > >> > >> > > >>> >> > the > >> > >> > > >>> >> > > > > best option. > >> > >> > > >>> >> > > > > > >> > >> > > >>> >> > > > > Can you clarify > >> > >> > > >>> >> > > > >> The server will simply leave out the features > >> whose > >> > >> > minimum > >> > >> > > >>> >> > supported > >> > >> > > >>> >> > > > > value is 0 for clients that send v3 > >> > >> > > >>> >> > > > > > >> > >> > > >>> >> > > > > For 3.8, I planned to set the 0s in the > response to > >> > 1. > >> > >> Is > >> > >> > it > >> > >> > > >>> better > >> > >> > > >>> >> > to > >> > >> > > >>> >> > > > > suppress the zero version features in the > response > >> > so we > >> > >> > are > >> > >> > > >>> >> > consistent > >> > >> > > >>> >> > > > > between trunk and 3.8? > >> > >> > > >>> >> > > > > > >> > >> > > >>> >> > > > > Thanks, > >> > >> > > >>> >> > > > > Justine > >> > >> > > >>> >> > > > > > >> > >> > > >>> >> > > > > On Fri, Jun 21, 2024 at 4:34 PM Colin McCabe < > >> > >> > > >>> cmcc...@apache.org> > >> > >> > > >>> >> > wrote: > >> > >> > > >>> >> > > > > > >> > >> > > >>> >> > > > >> Hi all, > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> It seems that there was a bug in older > versions of > >> > >> Kafka > >> > >> > > which > >> > >> > > >>> >> > caused > >> > >> > > >>> >> > > > >> deserialization problems when a supported > feature > >> > range > >> > >> > > >>> included > >> > >> > > >>> >> 0. > >> > >> > > >>> >> > For > >> > >> > > >>> >> > > > >> example, the range for group.version of [0, 1] > >> would > >> > >> be a > >> > >> > > >>> problem > >> > >> > > >>> >> in > >> > >> > > >>> >> > > > this > >> > >> > > >>> >> > > > >> situation. > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> This obviously makes supportedVersions kind of > >> > useless. > >> > >> > Any > >> > >> > > >>> >> feature > >> > >> > > >>> >> > that > >> > >> > > >>> >> > > > >> doesn't exist today is effectively at v0 today > (v0 > >> > is > >> > >> > > >>> equivalent > >> > >> > > >>> >> to > >> > >> > > >>> >> > > > "off"). > >> > >> > > >>> >> > > > >> But if we can't declare that the server > supports > >> > [0, 1] > >> > >> > or > >> > >> > > >>> >> similar, > >> > >> > > >>> >> > we > >> > >> > > >>> >> > > > >> can't declare that it supports the feature > being > >> > off. > >> > >> > > >>> Therefore, > >> > >> > > >>> >> no > >> > >> > > >>> >> > > > rolling > >> > >> > > >>> >> > > > >> upgrades are possible. > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> We noticed this bug during the 3.8 release > when we > >> > >> > noticed > >> > >> > > >>> >> problems > >> > >> > > >>> >> > in > >> > >> > > >>> >> > > > >> upgrade tests. As an addendum to KIP-1022, > we're > >> > adding > >> > >> > the > >> > >> > > >>> >> > following > >> > >> > > >>> >> > > > >> solution: > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> - There will be a new v4 for ApiVersionsRequest > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> - Clients that sent v4 will promise to > correctly > >> > handle > >> > >> > > ranges > >> > >> > > >>> >> that > >> > >> > > >>> >> > > > start > >> > >> > > >>> >> > > > >> with 0, such as [0, 1] > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> - The server will simply leave out the features > >> > whose > >> > >> > > minimum > >> > >> > > >>> >> > supported > >> > >> > > >>> >> > > > >> value is 0 for clients that send v3 > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> - ApiVersionsRequest v4 will be supported in AK > >> 3.9 > >> > and > >> > >> > > >>> above. AK > >> > >> > > >>> >> > 3.8 > >> > >> > > >>> >> > > > will > >> > >> > > >>> >> > > > >> ship with ApiVersionsRequest v3 just as today. > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> thanks, > >> > >> > > >>> >> > > > >> Colin > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > >> On Mon, Apr 15, 2024, at 11:01, Justine Olshan > >> > wrote: > >> > >> > > >>> >> > > > >> > Hey folks, > >> > >> > > >>> >> > > > >> > > >> > >> > > >>> >> > > > >> > Thanks everyone! I will go ahead and call it. > >> > >> > > >>> >> > > > >> > The KIP passes with the following +1 votes: > >> > >> > > >>> >> > > > >> > > >> > >> > > >>> >> > > > >> > - Andrew Schofield (non-binding) > >> > >> > > >>> >> > > > >> > - David Jacot (binding) > >> > >> > > >>> >> > > > >> > - José Armando García Sancio (binding) > >> > >> > > >>> >> > > > >> > - Jun Rao (binding) > >> > >> > > >>> >> > > > >> > > >> > >> > > >>> >> > > > >> > Thanks again, > >> > >> > > >>> >> > > > >> > Justine > >> > >> > > >>> >> > > > >> > > >> > >> > > >>> >> > > > >> > On Fri, Apr 12, 2024 at 11:16 AM Jun Rao > >> > >> > > >>> >> <j...@confluent.io.invalid > >> > >> > > >>> >> > > > >> > >> > > >>> >> > > > >> wrote: > >> > >> > > >>> >> > > > >> > > >> > >> > > >>> >> > > > >> >> Hi, Justine, > >> > >> > > >>> >> > > > >> >> > >> > >> > > >>> >> > > > >> >> Thanks for the KIP. +1 > >> > >> > > >>> >> > > > >> >> > >> > >> > > >>> >> > > > >> >> Jun > >> > >> > > >>> >> > > > >> >> > >> > >> > > >>> >> > > > >> >> On Wed, Apr 10, 2024 at 9:13 AM José Armando > >> > García > >> > >> > > Sancio > >> > >> > > >>> >> > > > >> >> <jsan...@confluent.io.invalid> wrote: > >> > >> > > >>> >> > > > >> >> > >> > >> > > >>> >> > > > >> >> > Hi Justine, > >> > >> > > >>> >> > > > >> >> > > >> > >> > > >>> >> > > > >> >> > +1 (binding) > >> > >> > > >>> >> > > > >> >> > > >> > >> > > >>> >> > > > >> >> > Thanks for the improvement. > >> > >> > > >>> >> > > > >> >> > -- > >> > >> > > >>> >> > > > >> >> > -José > >> > >> > > >>> >> > > > >> >> > > >> > >> > > >>> >> > > > >> >> > >> > >> > > >>> >> > > > >> > >> > >> > > >>> >> > > > > >> > >> > > >>> >> > > >> > >> > > >>> >> > > >> > >> > > >>> >> > > >> > >> > > >>> >> > -- > >> > >> > > >>> >> > -José > >> > >> > > >>> >> > > >> > >> > > >>> >> > >> > >> > > >>> > >> > >> > > >> > >> > >> > > > >> > >> > > >> > >> > >> > > >> >
