Troubleshooting Elastic Search Cluster

Problem: ES Update fails due to Index becomes readOnly

Root cause:

Elasticsearch automatically sets "read_only_allow_delete": "true" when hard disk space is low.

Fix:
PUT your_index_name/_settings
{
 "index": {
   "blocks": {
     "read_only_allow_delete": "false"
    }
  }
}

Om Terminal
$ curl -XPUT -H "Content-Type: application/json" \
   http://kibana_end_point_<localhost:9200/_all>/_settings \
     -d '{"index.blocks.read_only_allow_delete": false}'