Guidance for cluster upgrade

[philipstreet]

Is there any general guidance for upgrading a cluster? For example, the sequence of nodes upgraded (secondary ones first and then primary, or other way round) or it doesn't matter? Take them all offline, or can some of them be online whilst one of them is upgraded?

[ShreyasZare]

Thanks for asking. The order wont matter but upgrading secondary nodes first is recommended. You will need to upgrade all nodes to current version for the cluster to work correctly due to breaking changes.

[philipstreet]

OK, thanks for answering so quickly @ShreyasZare! I'll give it a go and report back if I have any isses.