Upgrade path from Zookeeper 3.4.6 to 3.6.1

Question

I've been tasked with updating several zookeeper clusters. We are currently running 3.4.6, and I'm wondering if I can go directly to 3.6.1, or if I have to upgrade to a 3.5.x version first, then on to 3.6.1.

I've found https://cwiki.apache.org/confluence/display/ZOOKEEPER/Upgrade+FAQ, which talks mostly about upgrading to 3.5.5. https://zookeeper.apache.org/doc/r3.5.3-beta/zookeeperReconfig.html#ch_reconfig_upgrade talks about upgrading to 3.5.0.

Has anyone else out there done this? I'm aware of the snapshot.0 issue.

Thanks, Todd

Answer 1

I have been tried to upgrade from 3.4.6 directly to 3.6.1, it works, just when upgrading old Leader node it shows won't find snapshot, all you need to do is to cleanup data storage(make a backup first), then restart the node.

so for the steps, you have A,B,C three nodes A with myid=11, B with myid=12, C with myid=13, then you have a A:11, B:12, C:13(Leader) Cluster.

upgrade A and B to 3.6.1 directly, watch there status and check if they are synced with C Leader.

stop C node, and B node should become Leader as it has the second biggest ID, after B node become Leader and A node still the follower, upgrade your C node to 3.6.1, and if there's any error, clean the data storage then restart.