How to define Pod health check port for livenessProbe/readinessProbe

Question

How do I define distinct Pod ports, one for application and another for health check (readinessProbe)?

Is the specification for ports, shown below, a correct way to make the readinessProbe to check the health check port TCP/9090 ? I mean, is the readinessProbe going to reach port 9090 (assuming it is open by the running container of course) ? Or does one need to specify any other port (nodePort, targetPort, port, whatever) ?

kind: Deployment
spec:
  template:
    spec:
      containers:
      - name: myapp
        image: <image>
        ports:
        - name: myapp-port
          containerPort: 8080
          protocol: TCP
        - name: healthcheck-port
          containerPort: 9090
          protocol: TCP

        readinessProbe:
          httpGet:
            port: healthcheck-port
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          periodSeconds: 10
          successThreshold: 2
          failureThreshold: 2

Answer 1

Yes, your specification snippet is almost correct. You don't need to specify any thing else to make readiness probe work.

Port names cannot be more than 15 characters, so the name healthcheck-port won't work. You might want to change the name to something smaller like healthcheck.