Set appProtocol for service resources (compatibility with service mesh)

[Florian Kaiser]

Hi. Currently there is no way to specify the appProtocol for services created by the operator. Unfortunately Microsoft's service mesh (Open Service Mesh) assumes the appProtocol is HTTP, which breaks Kafka and ZooKeeper. Please add appProtocol to all service ports or offer a way to customize it (e.g. something like podTemplate in the CRD but for the services).

Application protocol

FEATURE STATE: Kubernetes v1.20 [stable]

The appProtocol field provides a way to specify an application protocol for each Service port. The value of this field is mirrored by the corresponding Endpoints and EndpointSlice objects.

This field follows standard Kubernetes label syntax. Values should either be IANA standard service names or domain prefixed names such as mycompany.com/my-custom-protocol.

• Kubernetes docs: https://kubernetes.io/docs/concepts/services-networking/service/#application-protocol
• Open Service Mesh docs: https://release-v1-2.docs.openservicemesh.io/docs/guides/app_onboarding/app_protocol_selection/

e.g.

apiVersion: v1
kind: Service
metadata:
  name: kafka
spec:
  ports:
  - name: external
    port: 9092
    protocol: tcp
    appProtocol: tcp
    targetPort: 9092
  - name: http-external
    port: 8090
    protocol: tcp
    appProtocol: http
    targetPort: 8090
  - name: internal
    port: 9071
    protocol: tcp
    appProtocol: tcp
    targetPort: 9071
  - name: jmx
    port: 7203
    protocol: tcp
    appProtocol: tcp
    targetPort: 7203
  - name: jolokia
    port: 7777
    protocol: tcp
    appProtocol: http
    targetPort: 7777
  - name: prometheus
    port: 7778
    protocol: tcp
    appProtocol: http
    targetPort: 7778
  - name: replication
    port: 9072
    protocol: tcp
    appProtocol: tcp
    targetPort: 9072

apiVersion: v1
kind: Service
metadata:
  name: zookeeper
spec:
  ports:
  - name: client
    port: 2181
    protocol: tcp
    appProtocol: tcp
    targetPort: 2181
  - name: jmx
    port: 7203
    protocol: tcp
    appProtocol: tcp
    targetPort: 7203
  - name: jolokia
    port: 7777
    protocol: tcp
    appProtocol: http
    targetPort: 7777
  - name: leader-election
    port: 3888
    protocol: tcp
    appProtocol: tcp
    targetPort: 3888
  - name: peer
    port: 2888
    protocol: tcp
    appProtocol: tcp
    targetPort: 2888
  - name: prometheus
    port: 7778
    protocol: tcp
    appProtocol: http
    targetPort: 7778