According to this SO question [1], it seems that Zk 3.5 clients cannot talk to 3.4 servers. I also tried it out with a local deployment and Flink was not able to start.
Newer Zk versions can talk to older Zk servers if no new APIs are used [2]. [1] https://stackoverflow.com/a/61630617/4815083 [2] https://zookeeper.apache.org/releases.html Cheers, Till On Thu, Nov 25, 2021 at 10:39 PM Chesnay Schepler <ches...@apache.org> wrote: > I included the user ML in the thread. > > @users Are you still using Zookeeper 3.4? If so, were you planning to > upgrade Zookeeper in the near future? > > I'm not sure about ZK compatibility, but we'd also upgrade Curator to > 5.x, which doesn't support ookeeperK 3.4 anymore. > > On 25/11/2021 21:56, Till Rohrmann wrote: > > Should we ask on the user mailing list whether anybody is still using > > ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper > > 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that not a > > lot of users depend on it but just to make sure that we aren't annoying a > > lot of our users with this change. Apart from that +1 for removing it if > > not a lot of user depend on it. > > > > Cheers, > > Till > > > > On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl <matth...@ververica.com> > > wrote: > > > >> Thanks for starting this discussion, Chesnay. +1 from my side. It's > time to > >> move forward with the ZK support considering the EOL of 3.4 you already > >> mentioned. The benefits we gain from upgrading Curator to 5.x as a > >> consequence is another plus point. Just for reference on the > inconsistent > >> state issue you mentioned: FLINK-24543 [1]. > >> > >> Matthias > >> > >> [1] https://issues.apache.org/jira/browse/FLINK-24543 > >> > >> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler <ches...@apache.org> > >> wrote: > >> > >>> Hello, > >>> > >>> I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the > >>> default to 3.5 with an opt-in for 3.6. > >>> > >>> Supporting Zookeeper 3.4 (which is already EOL) prevents us from > >>> upgrading Curator to 5.x, which would allow us to properly fix an issue > >>> with inconsistent state. It is also required to eventually support ZK > >> 3.6. > > >
