Elastic ECK Filebeat logs from a specific pod

Question

I have configured an Elastic ECK Beat with autodiscover enabled for all pod logs, but I need to add logs from a specific pod log file too; from this path /var/log/traefik/access.log inside the container. I've tried with module and log config but still nothing works.

The access.log file exists on the pods and contains data. The filebeat index does not show any data from this log.file.path

Here is the Beat yaml:

---
apiVersion: beat.k8s.elastic.co/v1beta1
kind: Beat
metadata:
  name: filebeat
  namespace: elastic
spec:
  type: filebeat
  version: 8.3.1
  elasticsearchRef:
    name: elasticsearch
  kibanaRef:
    name: kibana
  config:
    filebeat:
      autodiscover:
        providers:
          - type: kubernetes
            node: ${NODE_NAME}
            hints:
              enabled: true
              default_config:
                type: container
                paths:
                  - /var/log/containers/*${data.kubernetes.container.id}.log
            templates:
              - condition.contains:
                  kubernetes.pod.name: traefik
                config:
                  - module: traefik
                    access:
                      enabled: true
                      var.paths: [ "/var/log/traefik/*access.log*" ]
    processors:
      - add_cloud_metadata: {}
      - add_host_metadata: {}
  daemonSet:
    podTemplate:
      spec:
        serviceAccountName: filebeat
        automountServiceAccountToken: true
        terminationGracePeriodSeconds: 30
        dnsPolicy: ClusterFirstWithHostNet
        hostNetwork: true # Allows to provide richer host metadata
        containers:
          - name: filebeat
            securityContext:
              runAsUser: 0
              # If using Red Hat OpenShift uncomment this:
              #privileged: true
            volumeMounts:
              - name: varlogcontainers
                mountPath: /var/log/containers
              - name: varlogpods
                mountPath: /var/log/pods
              - name: varlibdockercontainers
                mountPath: /var/lib/docker/containers
              - name: varlog
                mountPath: /var/log
            env:
              - name: NODE_NAME
                valueFrom:
                  fieldRef:
                    fieldPath: spec.nodeName
        volumes:
          - name: varlogcontainers
            hostPath:
              path: /var/log/containers
          - name: varlogpods
            hostPath:
              path: /var/log/pods
          - name: varlibdockercontainers
            hostPath:
              path: /var/lib/docker/containers
          - name: varlog
            hostPath:
              path: /var/log
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: filebeat
  namespace: elastic
rules:
  - apiGroups: [""] # "" indicates the core API group
    resources:
      - namespaces
      - pods
      - nodes
    verbs:
      - get
      - watch
      - list
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: filebeat
  namespace: elastic
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: filebeat
  namespace: elastic
subjects:
  - kind: ServiceAccount
    name: filebeat
    namespace: elastic
roleRef:
  kind: ClusterRole
  name: filebeat
  apiGroup: rbac.authorization.k8s.io

Here is the module loaded from Filebeat Logs:

...
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.337Z","log.logger":"esclientleg","log.origin":{"file.name":"eslegclient/connection.go","file.line":291},"message":"Attempting to connect to Elasticsearch version 8.3.1","service.name":"filebeat","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.352Z","log.logger":"modules","log.origin":{"file.name":"fileset/modules.go","file.line":108},"message":"Enabled modules/filesets: traefik (access)","service.name":"filebeat","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.353Z","log.logger":"input","log.origin":{"file.name":"log/input.go","file.line":172},"message":"Configured paths: [/var/log/traefik/*access.log*]","service.name":"filebeat","input_id":"fa247382-c065-40ca-974e-4b69f14c3134","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.355Z","log.logger":"modules","log.origin":{"file.name":"fileset/modules.go","file.line":108},"message":"Enabled modules/filesets: traefik (access)","service.name":"filebeat","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.355Z","log.logger":"input","log.origin":{"file.name":"log/input.go","file.line":172},"message":"Configured paths: [/var/log/traefik/*access.log*]","service.name":"filebeat","input_id":"6883d753-f149-4a68-9499-fe039e0de899","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.437Z","log.origin":{"file.name":"input/input.go","file.line":134},"message":"input ticker stopped","service.name":"filebeat","ecs.version":"1.6.0"}
{"log.level":"info","@timestamp":"2022-08-18T19:58:55.439Z","log.logger":"input","log.origin":{"file.name":"log/input.go","file.line":172},"message":"Configured paths: [/var/log/containers/*9a1680222e867802388f649f0a296e076193242962b28eb7e0e575bf68826d85.log]","service.name":"filebeat","input_id":"3c1fffae-0213-4889-b0e7-5dda489eeb51","ecs.version":"1.6.0"}
...

Answer 1

Docker logging is based on the stdout/stderr output of a container. If you only write into a log file inside a container it will never be picked up by Docker logging and can therefore also not be processed by your Filebeat setup.

Instead ensure that all logs generated by your containers are sent to stdout. Which would mean in your example start the Traeffic pod with --accesslogsfile=/dev/stdout to also send the access logs to stdout instead of the log file.