I have a 2.3.3 elasticsearch cluster and I mistakenly joined a 2.4.1 node.
The problem is that somehow I lost two nodes in the cluster and I ended up with a primary shard on the 2.4.1 node and two unassigned replicas of that same shard. (Total replica count per shard is 3)
The cluster state is therefore yellow.
I have tried relocating the primary shard on another node but :
target node version [2.3.3] is older than source node version [2.4.1]
Same thing goes for trying to assign the two unassigned shards to 2.3.3 nodes.
Also I have tried cancelling placement of the primary shard on the 2.4.1 machine and It didn't work either.
Do you have any ideas how I can solve this? First thing that comes to my mind is upgrading the other nodes to 2.4.1 but let's say that is not an option.
I would really appreciate it if you took your time to answer this because I'm completely out of ideas.
Thank you for your time.