Problem occured with same name of cluster in different machines

Elastic Stack Elasticsearch
1

Hello,

I have a weird issue today and it gives me lots of problem. I had two cluster different but unfortunatelly I gave them the same names by mistake;

lets say;
test_cluster

both cluster have had totaly different machines ( it was working well its been one month)
today I added a machine in one of the cluster and I saw that all the machines were in the same cluster physically (it was not the case before adding the machine)
I have chacked the unicast list; there were no machine in common
So someone can explain me how I had this problem and how I can seperate them ?

Thank you

2

This is why - https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery-zen.html#multicast

Your best option is to use https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules-allocation.html#shard-allocation-filtering and then move indices to their correct node, then shutdown one cluster and change the cluster name.