ElasticSearch: Unassigned Shards, how to fix?

Question

I have an ES cluster with 4 nodes:

number_of_replicas: 1
search01 - master: false, data: false
search02 - master: true, data: true
search03 - master: false,          


        

Answer 1

In my case an old node with old shares was joining the cluster, so we had to shutdown the old node and delete the indices with unassigned shards.