2.3 and 2.4 in the same cluster?

I've tried Google, this forum and the ElasticSearch docs but I can't find a definitive answer.

When using the yum repository for ElasticSearch 2.x I've been happily using version 2.3.4 for some time.

The other day I joined a few more nodes to the cluster and installed ElasticSearch from the same repo and got version 2.4.

The cluster looks happy enough and I'm assuming since 2.3 and then 2.4 shipped from the same repo that all will be well, but before I do this I upgrade production I wondered if all the 2.x releases are compatible and happy to work together?

Thanks!

Pete

Have a read of this chapter - https://www.elastic.co/guide/en/elasticsearch/reference/2.3/setup-upgrade.html

But you really need to upgrade all nodes.

Hi Mark,

Thanks for reply.

Yes, I read that and I didn't really get an idea for running 2.3 and 2.4 together. Upgrading them all does sound sensible.

Let me give a bit more context...

Our production environment has ElasticSearch 2.3 installed from the 2.x repos on CentOS 7. Our sys admins like to run yum update fairly routinely to maintain security patches for the OS, etc. and this will (eventually) upgrade our production environment to 2.4.

However, our development environment is under our control and I recently upgraded half the cluster from 1.6 to 2.3 4. When I came to upgrading the other half it went to 2.4.

There is no problem upgrading the first half from 2.3 to 2.4, but then that leaves our development cluster on a different version to the production cluster.

So perhaps the better question would be - are the differences between 2.3 and 2.4 significant enough to warrent downgrading development to 2.3.5 and no longer using the repos?

I read the "breaking changes" and the "release notes" and nothing really stood out.

Thanks again!

Pete

https://www.elastic.co/guide/en/elasticsearch/reference/2.3/rolling-upgrades.html#rolling-upgrades

Running multiple versions of Elasticsearch in the same cluster for any length of time beyond that required for an upgrade is not supported

If you are using repos, then just specify the version you want to install. Consult man yum for how to do that.

Thanks Mark!

Figured it out now:

yum install elasticsearch-2.3.4-1

rather than:

yum install elasticsearch

should anyone else wonder.