The section in our docs on JDK11 seems out of date. In my experience using Java 11 to run ZooKeeper (3.5), Hadoop HDFS/YARN/MR (2.10 and 3.3), and HBase (2.4) is a nonissue. These software versions are stable under load. Most recently I tested scale ingest with 11.0.15+1, hot off the presses so to speak. No issues to report — although, I cannot claim this is the production configuration where I work yet. Perhaps near the end of 2022. Anyway, I think mine is likely not the only experience like this so the hedging language can be removed from the text, especially if someone else writes in with positive testimonial.
Regarding the original question, I would be in favor of the proposal. Time matches on. I assume just to state the obvious that our destination of minimum LTS would shift from 8 to 11. I also agree it would be good to move up from EOL or soon to be EOL versions of our dependencies. Looks like ZooKeeper 3.6 will be the lowest live code line by the end of this year. Hadoop 2 isn’t exactly dead, at least the source branch is still receiving occasional update, but is not releasing. We should probably consider it effectively EOL. The Hadoop minimum could become 3.3. The primary consideration to my mind is the state of S3A: in what version it can be said to be stable and feature complete. I think 3.3 is the appropriate code line for that criteria but perhaps 3.2 could serve as well. > On Feb 15, 2022, at 10:48 AM, Sean Busbey <bus...@apache.org> wrote: > > Hi folks! > > It's been some time since we decided to stick to LTS JDK releases as a way > of getting a handle on the JDK treadmill. > > What do folks think about deprecating JDK8? The openjdk8u project is still > going and there are commercial support options at least through 2030. > > Deprecating it in HBase 3 would mean we could remove it in HBase 4, not > that we would _have_ to remove it. The way I think about likely timing of > these events goes like this: > > * HBase 2 started alphas in June 2017, betas in January 2018, and came out > in April 2018 > * HBase 3 started alphas in July 2021, and as of Feb 2022 we haven't > discussed how close we are to our stated beta goals (upgrades from active > 2.x releases and removal of not-ready features). > > Given the above, in the absence of us specifically pushing to roll through > major version numbers for some reason, I think a reasonably conservative > estimate is for HBase 3 to arrive in late 2022 or early 2023 and then HBase > 4 to start alphas in ~2025. An HBase 5 prior to 2030 seems unlikely. > > That all said, our current reference guide section on java versions does > not sound very confident about JDK11 support. > >> A Note on JDK11 * >> Preliminary support for JDK11 is introduced with HBase 2.3.0. This > support is limited to >> compilation and running the full test suite. There are open questions > regarding the runtime >> compatibility of JDK11 with Apache ZooKeeper and Apache Hadoop > (HADOOP-15338). >> Significantly, neither project has yet released a version with explicit > runtime support for >> JDK11. The remaining known issues in HBase are catalogued in HBASE-22972. >> > > Since that blurb was written, Hadoop has added JDK11 support [1] as has > ZooKeeper[2]. As a part of buttoning up our JDK11 support we could update > our minimum supported versions of these projects to match that support. > > What do folks think? > > [1]: https://hadoop.apache.org/docs/r3.3.0/index.html > [2]: > https://zookeeper.apache.org/doc/r3.6.0/zookeeperAdmin.html#sc_systemReq
