yeah, I remember something... I think that was about the leader election protocol (between ZooKeeper servers), which changed somewhat around the introduction of dynamic reconfig, and you need a relatively late ZooKeeper 3.4 version to be able to communicate (and form a quorum) together with newer ZooKeeper servers. I am not sure which 3.4 version is safe to use, but I would recommend the following upgrade path: - 3.4.6 -> 3.4.14 (latest 3.4) - 3.4.14 -> 3.5.9 (latest 3.5) - 3.5.9 -> 3.8.0 (currently the latest 3.8)
I think I tested these above rolling upgrades already, but I would definitely advise you to try everything out on some test cluster (with live test traffic) before you would do it in production. I am not sure if 3.4.14 -> 3.8.0 works (I don't remember testing it), but it might work as well. Also some upgrade related info you might find interesting: https://cwiki.apache.org/confluence/display/ZOOKEEPER/Upgrade+FAQ Best regards, Máté On Tue, Aug 23, 2022 at 4:09 AM Will Now <[email protected]> wrote: > I'm planning to do a rolling upgrade from 3.4.6 to 3.8.0. While > researching zookeeper recently I could swear that I stumbled across some > documentation with some warnings about 3.4.6. Specifically it sounded like > you might encounter failures during the upgrade if you jumped straight from > 3.4.6 to 3.8.0 (and other newer versions also perhaps). > > I recall that it was recommended to first upgrade to 3.4.10 and THEN jump > to the 3.8.0 version. > > I am now feeling like I dreamt all of this because i cannot locate that > information for the life of me. Does this ring a bell with anyone? Perhaps > you can send me a link or tell me I'm losing it (or both)? Thanks! >
