How Do You Define a Kubernetes Service TargetPort as a String?

A simple example of defining the targetPort as string is to first define it in the Deployment before you can refer to it as a string in targetPort in a service. Below is the simple example to show how to map "http" ( port name) from deployment in a service targetPort spec.

Deployment:

apiVersion: apps/v1kind: Deploymentmetadata:  name: backendspec:  selector:    matchLabels:      app: hello      tier: backend      track: stable  replicas: 3  template:    metadata:      labels:        app: hello        tier: backend        track: stable    spec:      containers:        - name: hello          image: "gcr.io/google-samples/hello-go-gke:1.0"          ports:            - name: http              containerPort: 80

Service:

apiVersion: v1kind: Servicemetadata:  name: hellospec:  selector:    app: hello    tier: backend  ports:  - protocol: TCP    port: 80    targetPort: http

You can set targetPort to an integer value or a name.

If you refer to it by name, that name has to be defined within the pod(s) in spec > containers[n] > ports[n] > name

If you refer by integer, there is no need to define ports in pods at all, although it's reasonable to still do it for clarity.

By providing a matching port name in the Deployment, things appear to work properly:

ports:- name: web  containerPort: 80