On Tue, May 5, 2020, at 12:36, Ryanne Dolan wrote: > > In 3.0 it sounds like nothing is breaking and our big change won't be > > complete... so, what's the motivation for the major release? > > Exactly. Why would 3.1 be the breaking release? No one would expect > everything to break going from 3.0 to 3.1 >
Hi Ryanne, That's right. Kafka uses Semantic Versioning. See https://semver.org/. The short summary is that we can't make incompatible changes in minor releases. So the decision to move from 2.x to 3.0 isn't really about the number of new features or changes, but just about whether the new release is 100% compatible with the old. Most users never encounter the incompatibilities, but it's important to set expectations that moving to a new 2.x release won't cause a compatibility break, but moving to a new major release might... IF you are using a deprecated feature. Or sometimes if you are using an old JVM you will need to upgrade to upgrade major releases. best, Colin > > On Tue, May 5, 2020 at 2:34 PM Gwen Shapira <g...@confluent.io> wrote: > > > It sounds like the decision to make the next release 3.0 is a bit arbitrary > > then? > > > > With Exactly Once, we announced 1.0 as one release after the one where EOS > > shipped, when we felt it was "ready" (little did we know... but that's > > another story). > > 2.0 was breaking due to us dropping Java 7. > > > > In 3.0 it sounds like nothing is breaking and our big change won't be > > complete... so, what's the motivation for the major release? > > > > On Tue, May 5, 2020 at 12:12 PM Guozhang Wang <wangg...@gmail.com> wrote: > > > > > I think there's a confusion regarding the "bridge release" proposed in > > > KIP-500: should it be release "3.0" or be release "2.X" (i.e. the last > > > minor release before 3.0). > > > > > > My understanding is that "3.0" would be the bridge release, i.e. it would > > > not break any compatibility, but 3.1 potentially would, so an upgrade > > from > > > 2.5 to 3.1 would need to first upgrade to 3.0, and then to 3.1. For > > > clients, all broker-client compatibility are still maintained 3.1+ so > > that > > > 2.x producer / consumer clients could still talk to 3.1+ brokers, only > > > those old versioned scripts with on "--zookeeper" would not work with > > 3.1+ > > > brokers anymore since there are no zookeepers. > > > > > > > > > Guozhang > > > > > > On Mon, May 4, 2020 at 5:33 PM Gwen Shapira <g...@confluent.io> wrote: > > > > > > > +1 for removing MM 1.0 when we cut a breaking release. It is sad to see > > > > that we are still investing in it (I just saw a KIP toward improving > > its > > > > reset policy). > > > > > > > > My understanding was that KIP-590 is not breaking compatibility, I > > think > > > > Guozhang said that in response to my question on the discussion thread. > > > > > > > > Overall, since Kafka has time-based releases, we can make the call on > > 3.0 > > > > vs 2.7 when we are at "KIP freeze date" and can see which features are > > > > likely to make it. > > > > > > > > > > > > On Mon, May 4, 2020 at 5:13 PM Ryanne Dolan <ryannedo...@gmail.com> > > > wrote: > > > > > > > > > Hey Colin, I think we should wait until after KIP-500's "bridge > > > release" > > > > so > > > > > there is a clean break from Zookeeper after 3.0. The bridge release > > by > > > > > definition is an attempt to not break anything, so it theoretically > > > > doesn't > > > > > warrant a major release. If that's not the case (i.e. if a single > > > "bridge > > > > > release" turns out to be impractical), we should consider forking 3.0 > > > > while > > > > > maintaining a line of Zookeeper-dependent Kafka in 2.x. That way 3.x > > > can > > > > > evolve dramatically without breaking the 2.x line. In particular, > > > > anything > > > > > related to removing Zookeeper could land in pre-3.0 while every other > > > > > feature targets 2.6. > > > > > > > > > > If you are proposing 2.6 should be the "bridge release", I think this > > > is > > > > > premature given Kafka's time-based release schedule. If the bridge > > > > features > > > > > happen to be merged before 2.6's feature freeze, then sure -- let's > > > make > > > > > that the bridge release in retrospect. And if we get all the > > > > post-Zookeeper > > > > > features merged before 2.7, I'm onboard with naming it "3.0" instead. > > > > > > > > > > That said, we should aim to remove legacy MirrorMaker before 3.0 as > > > well. > > > > > I'm happy to drive that additional breaking change. Maybe 2.6 can be > > > the > > > > > "bridge" for MM2 as well. > > > > > > > > > > Ryanne > > > > > > > > > > On Mon, May 4, 2020, 5:05 PM Colin McCabe <cmcc...@apache.org> > > wrote: > > > > > > > > > > > Hi all, > > > > > > > > > > > > We've had a few proposals recently for incompatible changes. One > > of > > > > them > > > > > > is my KIP-604: Remove ZooKeeper Flags from the Administrative > > Tools. > > > > The > > > > > > other is Boyang's KIP-590: Redirect ZK Mutation Protocols to the > > > > > > Controller. I think it's time to start thinking about Kafka 3.0. > > > > > > Specifically, I think we should move to 3.0 after the 2.6 release. > > > > > > > > > > > > From the perspective of KIP-500, in Kafka 3.x we'd like to make > > > running > > > > > in > > > > > > a ZooKeeper-less mode possible (but not yet the default.) This is > > > the > > > > > > motivation behind KIP-590 and KIP-604, as well as some of the other > > > > KIPs > > > > > > we've done recently. Since it will take some time to stabilize the > > > new > > > > > > ZooKeeper-free Kafka code, we will hide it behind an option > > > initially. > > > > > > (We'll have a KIP describing this all in detail soon.) > > > > > > > > > > > > What does everyone think about having Kafka 3.0 come up next after > > > 2.6? > > > > > > Are there any other things we should change in the 2.6 -> 3.0 > > > > transition? > > > > > > > > > > > > best, > > > > > > Colin > > > > > > > > > > > > > > > > > > > > > > > -- > > > > Gwen Shapira > > > > Engineering Manager | Confluent > > > > 650.450.2760 | @gwenshap > > > > Follow us: Twitter | blog > > > > > > > > > > > > > -- > > > -- Guozhang > > > > > > > > > -- > > Gwen Shapira > > Engineering Manager | Confluent > > 650.450.2760 | @gwenshap > > Follow us: Twitter | blog > > >
