Master not discovered exception

Elastic Stack Elasticsearch
1

We have an elasticsearch cluster of 2 masters et 6 data nodes since 2 years. Yesterday, requests became very slow, we started experiencing a time out in elasticsearch and kibana.

We then discovered this on one of the two master nodes:


(SFPP....) /home/rmen023 $curl -X GET "server:9200/_                                                                                 cluster/health?pretty" 
Enter host password :
{
  "error" : {
    "root_cause" : [
      {
        "type" : "master_not_discovered_exception",
        "reason" : null
      }
    ],
    "type" : "master_not_discovered_exception",
    "reason" : null
  },
  "status" : 503
}

Any idea? It is the first time for us to see this.

2

Would it be possible for you to share the Elasticsearch logs?