CODEWITHSUNDEEP
apache-zookeeper
Ztyx
Ztyx

Reputation: 14908

What do I need to know when upgrading Zookeeper from 3.3.X to 3.4.X?

I have a Zookeeper ensemble I'd like to upgrade from 3.3.X to 3.4.X branch. Can this be done on a live cluster? Requires downtime? Are there any instructions to be found on this somewhere?

Upvotes: 4

Views: 3920

Answers (1)

nicklu
nicklu

Reputation: 71

From what I checked ,

  1. What are the options/process for upgrading ZooKeeper?

There are two primary ways of doing this; 1) full restart or 2) rolling restart.

In the full restart case you can stage your updated code/configuration/etc..., stop all of the servers in the ensemble, switch code/configuration, and restart the ZooKeeper ensemble. If you do this programmatically (scripts typically, ie not by hand) the restart can be done on order of seconds. As a result the clients will lose connectivity to the ZooKeeper cluster during this time, however it looks to the clients just like a network partition. All existing client sessions are maintained and re-established as soon as the ZooKeeper ensemble comes back up. Obviously one drawback to this approach is that if you encounter any issues (it's always a good idea to test/stage these changes on a test harness) the cluster may be down for longer than expected. The second option, preferable for many users, is to do a "rolling restart". In this case you upgrade one server in the ZooKeeper ensemble at a time; bring down the server, upgrade the code/configuration/etc..., then restart the server. The server will automatically rejoin the quorum, update it's internal state with the current ZK leader, and begin serving client sessions. As a result of doing a rolling restart, rather than a full restart, the administrator can monitor the ensemble as the upgrade progresses, perhaps rolling back if any issues are encountered

I am thinking you need to download the file and extract to a local folder and transfer the configuration file/settings into the new version and have the old server down and run the new version server

https://wiki.apache.org/hadoop/ZooKeeper/FAQ

Upvotes: 7

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