I have a running ES 6.8.2 cluster and I want to upgrade it by launching new 7.8.1 nodes (non master), syncing them with the cluster, then launch the 7.8.1 master nodes and so on.
The problem is my new 7.8.1 nodes do not discover the 6.8.2 master using EC2 discovery. Tags are correct and validated. If I’m trying to discover 7.8.1 masters (as a test, from another cluster) it does work. The nodes have full permission to describe and filter ec2 instances so it’s not that (as I said the whole thing works when trying to discover 7.8.1 masters).
What am I missing? Is this not supposed to work because I’m launching fresh 7.8.1 nodes to discover existing 6.8.2 masters?