Thanks for the detailed thoughts, everyone. Eric (Badger), my understanding is the same as yours re. minor vs patch releases. As for putting features into minor/patch releases, if we keep the convention of putting new features only into minor releases, my assumption is still that it's unlikely people will want to get them into branch-2 (based on the 2.10.0 release process). For the java 11 issue, we haven't even really removed support for java 7 in branch-2 (much less java 8), so I feel moving to java 11 would go along with a move to branch 3. And as you mentioned, if people really want to use java 11 on branch-2, we can always revive branch-2. But for now I think the convenience of not needing to port to both branch-2 and branch-2.10 (and below) outweighs the cost of potentially needing to revive branch-2.
Jonathan Hung On Wed, Nov 20, 2019 at 10:50 AM Eric Yang <ey...@cloudera.com> wrote: > +1 for 2.10.x as last release for 2.x version. > > Software would become more compatible when more companies stress test the > same software and making improvements in trunk. Some may be extra caution > on moving up the version because obligation internally to keep things > running. Company obligation should not be the driving force to maintain > Hadoop branches. There is no proper collaboration in the community when > every name brand company maintains its own Hadoop 2.x version. I think it > would be more healthy for the community to reduce the branch forking and > spend energy on trunk to harden the software. This will give more > confidence to move up the version than trying to fix n permutations > breakage like Flash fixing the timeline. > > Apache license stated, there is no warranty of any kind for code > contributions. Fewer community release process should improve software > quality when eyes are on trunk, and help steering toward the same end goals. > > regards, > Eric > > > > On Tue, Nov 19, 2019 at 3:03 PM Eric Badger > <ebad...@verizonmedia.com.invalid> wrote: > >> Hello all, >> >> Is it written anywhere what the difference is between a minor release and >> a >> point/dot/maintenance (I'll use "point" from here on out) release? I have >> looked around and I can't find anything other than some compatibility >> documentation in 2.x that has since been removed in 3.x [1] [2]. I think >> this would help shape my opinion on whether or not to keep branch-2 alive. >> My current understanding is that we can't really break compatibility in >> either a minor or point release. But the only mention of the difference >> between minor and point releases is how to deal with Stable, Evolving, and >> Unstable tags, and how to deal with changing default configuration values. >> So it seems like there really isn't a big official difference between the >> two. In my mind, the functional difference between the two is that the >> minor releases may have added features and rewrites, while the point >> releases only have bug fixes. This might be an incorrect understanding, >> but >> that's what I have gathered from watching the releases over the last few >> years. Whether or not this is a correct understanding, I think that this >> needs to be documented somewhere, even if it is just a convention. >> >> Given my assumed understanding of minor vs point releases, here are the >> pros/cons that I can think of for having a branch-2. Please add on or >> correct me for anything you feel is missing or inadequate. >> Pros: >> - Features/rewrites/higher-risk patches are less likely to be put into >> 2.10.x >> - It is less necessary to move to 3.x >> >> Cons: >> - Bug fixes are less likely to be put into 2.10.x >> - An extra branch to maintain >> - Committers have an extra branch (5 vs 4 total branches) to commit >> patches to if they should go all the way back to 2.10.x >> - It is less necessary to move to 3.x >> >> So on the one hand you get added stability in fewer features being >> committed to 2.10.x, but then on the other you get fewer bug fixes being >> committed. In a perfect world, we wouldn't have to make this tradeoff. But >> we don't live in a perfect world and committers will make mistakes either >> because of lack of knowledge or simply because they made a mistake. If we >> have a branch-2, committers will forget, not know to, or choose not to >> (for >> whatever reason) commit valid bug fixes back all the way to branch-2.10. >> If >> we don't have a branch-2, committers who want their borderline risky >> feature in the 2.x line will err on the side of putting it into >> branch-2.10 >> instead of proposing the creation of a branch-2. Clearly I have made quite >> a few assumptions here based on my own experiences, so I would like to >> hear >> if others have similar or opposing views. >> >> As far as 3.x goes, to me it seems like some of the reasoning for killing >> branch-2 is due to an effort to push the community towards 3.x. This is >> why >> I have added movement to 3.x as both a pro and a con. As a community >> trying >> to move forward, keeping as many companies on similar branches as possible >> is a good way to make sure the code is well-tested. However, from a >> stability point of view, moving to 3.x is still scary and being able to >> stay on 2.x until you are comfortable to move is very nice. The 2.10.0 >> bridge release effort has been very good at making it possible for people >> to move from 2.x in 3.x, but the diff between 2.x and 3.x is so large that >> it is reasonable for companies to want to be extra cautious with 3.x due >> to >> potential performance degradation at large scale. >> >> A question I'm pondering is what happens when we move to Java 11 and >> someone is still on 2.x? If they want to backport HADOOP-15338 >> <https://issues.apache.org/jira/browse/HADOOP-15338> for Java 11 support >> to >> 2.x, surely not everyone is going to want that (at least not immediately). >> The 2.10 documentation states, "The JVM requirements will not change >> across >> point releases within the same minor release except if the JVM version >> under question becomes unsupported" [1], so this would warrant a 2.11 >> release until Java 8 becomes unsupported (though one could argue that it >> is >> already unsupported since Oracle is no longer giving public Java 8 >> update). >> If we don't keep branch-2 around now, would a Java 11 backport be the >> catalyst for a branch-2 revival? >> >> Not sure if this really leads to any sort of answer from me on whether or >> not we should keep branch-2 alive, but these are the things that I am >> weighing in my mind. For me, the bigger problem beyond having branch-2 or >> not is committers not being on the same page with where they should commit >> their patches. >> >> Eric >> >> [1] >> >> https://hadoop.apache.org/docs/r2.10.0/hadoop-project-dist/hadoop-common/Compatibility.html >> [2] >> >> https://hadoop.apache.org/docs/r3.0.0/hadoop-project-dist/hadoop-common/Compatibility.html >> >> On Tue, Nov 19, 2019 at 2:49 PM epa...@apache.org <epa...@apache.org> >> wrote: >> >> > Hi Konstantin, >> > >> > Sure, I understand those concerns. On the other hand, I worry about the >> > stability of 2.10, since we will be on it for a couple of years at >> least. >> > I worry >> > that some committers may want to put new features into a branch 2 >> release, >> > and without a branch-2, they will go directly into 2.10. Since we don't >> > always >> > catch corner cases or performance problems for some time (usually not >> > until >> > the release is deployed to a busy, 4-thousand node cluster), it may be >> > very >> > difficult to back out those changes. >> > >> > It sounds like I'm in the minority here, so I'm not nixing the idea, >> but I >> > do >> > have these reservations. >> > >> > Thanks, >> > -Eric >> > >> > >> > >> > On Tuesday, November 19, 2019, 1:04:15 AM CST, Konstantin Shvachko < >> > shv.had...@gmail.com> wrote: >> > Hi Eric, >> > >> > We had a long discussion on this list regarding making the 2.10 release >> the >> > last of branch-2 releases. We intended 2.10 as a bridge release between >> > Hadoop 2 and 3. We may have bug-fix releases or 2.10, but 2.11 is not in >> > the picture right now, and many people may object this idea. >> > >> > I understand Jonathan's proposal as an attempt to >> > 1. eliminate confusion which branches people should commit their >> back-ports >> > to >> > 2. save engineering effort committing to more branches than necessary >> > >> > "Branches are cheap" as our founder used to say. If we ever decide to >> > release 2.11 we can resurrect the branch. >> > Until then I am in favor of Jonathan's proposal +1. >> > >> > Thanks, >> > --Konstantin >> > >> > >> > On Mon, Nov 18, 2019 at 10:41 AM Jonathan Hung <jyhung2...@gmail.com> >> > wrote: >> > >> > > Thanks Eric for the comments - regarding your concerns, I feel the >> pros >> > > outweigh the cons. To me, the chances of patch releases on 2.10.x are >> > much >> > > higher than a new 2.11 minor release. (There didn't seem to be many >> > people >> > > outside of our company who expressed interest in getting new features >> to >> > > branch-2 prior to the 2.10.0 release.) Even now, a few weeks after >> 2.10.0 >> > > release, there's 29 patches that have gone into branch-2 and 9 in >> > > branch-2.10, so it's already diverged quite a bit. >> > > >> > > In any case, we can always reverse this decision if we really need >> to, by >> > > recreating branch-2. But this proposal would reduce a lot of confusion >> > IMO. >> > > >> > > Jonathan Hung >> > > >> > > >> > > On Fri, Nov 15, 2019 at 11:41 AM epa...@apache.org <epa...@apache.org >> > >> > > wrote: >> > > >> > > > Thanks Jonathan for opening the discussion. >> > > > >> > > > I am not in favor of this proposal. 2.10 was very recently released, >> > and >> > > > moving to 2.10 will take some time for the community. It seems >> > premature >> > > to >> > > > make a decision at this point that there will never be a need for a >> > 2.11 >> > > > release. >> > > > >> > > > -Eric >> > > > >> > > > >> > > > On Thursday, November 14, 2019, 8:51:59 PM CST, Jonathan Hung < >> > > > jyhung2...@gmail.com> wrote: >> > > > >> > > > Hi folks, >> > > > >> > > > Given the release of 2.10.0, and the fact that it's intended to be a >> > > bridge >> > > > release to Hadoop 3.x [1], I'm proposing we make 2.10.x the last >> minor >> > > > release line in branch-2. Currently, the main issue is that there's >> > many >> > > > fixes going into branch-2 (the theoretical 2.11.0) that's not going >> > into >> > > > branch-2.10 (which will become 2.10.1), so the fixes in branch-2 >> will >> > > > likely never see the light of day unless they are backported to >> > > > branch-2.10. >> > > > >> > > > To do this, I propose we: >> > > > >> > > > - Delete branch-2.10 >> > > > - Rename branch-2 to branch-2.10 >> > > > - Set version in the new branch-2.10 to 2.10.1-SNAPSHOT >> > > > >> > > > This way we get all the current branch-2 fixes into the 2.10.x >> release >> > > > line. Then the commit chain will look like: trunk -> branch-3.2 -> >> > > > branch-3.1 -> branch-2.10 -> branch-2.9 -> branch-2.8 >> > > > >> > > > Thoughts? >> > > > >> > > > Jonathan Hung >> > > > >> > > > [1] >> > > https://www.mail-archive.com/yarn-dev@hadoop.apache.org/msg29479.html >> > > > >> > > >> > >> > --------------------------------------------------------------------- >> > To unsubscribe, e-mail: common-dev-unsubscr...@hadoop.apache.org >> > For additional commands, e-mail: common-dev-h...@hadoop.apache.org >> > >> > >> >
