[filebeat] introduce dnsConfig values for the containers

filebeat/README.md

@@ -116,6 +116,7 @@ as a reference. They are also used in the automated testing of this chart.
 | `filebeatConfig`         | Allows you to add any config files in `/usr/share/filebeat` such as `filebeat.yml`                                                                                              | see [values.yaml][]                |
 | `fullnameOverride`       | Overrides the full name of the resources. If not set the name will default to " `.Release.Name` - `.Values.nameOverride or .Chart.Name` "                                       | `""`                               |
 | `hostNetworking`         | Use host networking in the DaemonSet so that hostname is reported correctly                                                                                                     | `false`                            |
+| `dnsConfig`              | Configurable [dnsConfig][]                                                                                                                                                      | `{}`                               |
 | `hostPathRoot`           | Fully-qualified [hostPath][] that will be used to persist Filebeat registry data                                                                                                | `/var/lib`                         |
 | `imagePullPolicy`        | The Kubernetes [imagePullPolicy][] value                                                                                                                                        | `IfNotPresent`                     |
 | `imagePullSecrets`       | Configuration for [imagePullSecrets][] so that you can use a private registry for your image                                                                                    | `[]`                               |
@@ -192,6 +193,7 @@ about our development and testing process.
 [filebeat oss docker image]: https://www.docker.elastic.co/#filebeat-7-7-0-oss
 [helm]: https://helm.sh
 [hostNetwork]: https://kubernetes.io/docs/concepts/policy/pod-security-policy/#host-namespaces
+[dnsConfig]: https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/
 [hostPath]: https://kubernetes.io/docs/concepts/storage/volumes/#hostpath
 [imagePullPolicy]: https://kubernetes.io/docs/concepts/containers/images/#updating-images
 [imagePullSecrets]: https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/#create-a-pod-that-uses-your-secret

filebeat/templates/daemonset.yaml

@@ -56,6 +56,9 @@ spec:
       hostNetwork: true
       dnsPolicy: ClusterFirstWithHostNet
       {{- end }}
+      {{- if .Values.dnsConfig }}
+      dnsConfig: {{ toYaml .Values.dnsConfig | nindent 8 }}
+      {{- end }}
       volumes:
       {{- range .Values.secretMounts }}
       - name: {{ .name }}

filebeat/values.yaml

@@ -51,6 +51,7 @@ envFrom: []
 # Root directory where Filebeat will write data to in order to persist registry data across pod restarts (file position and other metadata).
 hostPathRoot: /var/lib
 hostNetworking: false
+dnsConfig: {}
 image: "docker.elastic.co/beats/filebeat"
 imageTag: "7.7.1"
 imagePullPolicy: "IfNotPresent"