I'm deploying filebeat in kubernetes using the k8s manifests from here: https://raw.githubusercontent.com/elastic/beats/7.5/deploy/kubernetes/filebeat-kubernetes.yaml

The filebeat template is loaded into elasticsearch, but the mappings for nginx module are incomplete:

"nginx" : {
  "properties" : {
    "access" : {
      "properties" : {
        "geoip" : {
          "type" : "object"
        },
        "user_agent" : {
          "type" : "object"
        }
      }
    },
    "error" : {
      "properties" : {
        "connection_id" : {
          "type" : "long"
        }
      }
    }
  }
},

Most of the nginx properties defined in the fields.yaml are aliases and none of the properties defined as an alias are getting their way into the filebeat template.

Is there something I'm missing as part of the filebeat configuration ?

I also tried with my custom fields.yaml where I replaced the aliases with their concrete definition and the elasticsearh loaded mapping looks good.