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

This may be a cause of the disk space as well, In Elasticsearch 7.5.2, by default, if disk usage is above 85% then replica shards are not assigned to any other node.

This can be fixed by setting a different threshold or by disabling it either in the .yml or via Kibana

PUT _cluster/settings
{
  "persistent": {
    "cluster.routing.allocation.disk.threshold_enabled": "false"
  }
}