Enable logging in Elasticsearch/Kibana deployed using ECK

Objective: To configure logging into Elasticsearch/Kibana deployed by ECK.

Update your Elasticsearch deployment-

apiVersion: elasticsearch.k8s.elastic.co/v1
kind: Elasticsearch
metadata:
  name: MYECK
spec:
  version: 7.7.0
  nodeSets:
  - name: master
    count: 1
    config:
      logger.org.elasticsearch: warn
      node.master: true
      node.data: false
      node.ingest: false
      node.ml: false

Update your Kibana deployment

apiVersion: kibana.k8s.elastic.co/v1
kind: Kibana
metadata:
  name: mykibana
spec:
  version: 7.7.0
  count: 1
  elasticsearchRef:
    name: MYECK
  config:
    logging.quiet: true
  http:
    service:
      spec:
        type: ClusterIP
    tls:
      certificate:
        secretName: custom-ssl-cert

There is one more option using env variables !

# In Elasticsearch
podTemplate:
      spec:
        containers:
          - name: elasticsearch
            env:
              - name: logger.org.elasticsearch
                value: warn
---
# In kibana
podTemplate:
    spec:
      containers:
        - name: kibana
          env:
            - name: LOGGING_QUIET
              value: "true"

More Controls you need then use log4j

kubectl create configmap log4j --from-file=log4j2.properties=/opt/log4j2.properties

Mount it into your pod template

podTemplate:
      spec:
        containers:
        - name: elasticsearch
          volumeMounts:
          - mountPath: /usr/share/elasticsearch/config/log4j2.properties
            subPath: log4j2.properties
            name: log4j
        volumes:
        - name: log4j
          configMap:
            name: log4j

Ref:

https://www.elastic.co/guide/en/kibana/current/settings.html