I have a frontend React application and a Go backend service as the API for the frontend. Both are Kubernetes services in the same namespace. How can I communicate with the Go backend service without having to use an external IP? I got it to work with an external ip, but, I can't get the fqdn to resolve correctly like it should. The frontend service is built from the nginx:1.15.2-alpine docker image. How can I get the frontend React app to communicate with the backend Go server?

Frontend service.yaml:

apiVersion: v1
kind: Service
metadata:
  name: ui
  namespace: client
  labels:
    app: ui
spec:
  type: NodePort
  ports:
    - name: http
      port: 80
      targetPort: http
    - name: https
      port: 443
      targetPort: https
  selector:
    app: ui

Frontend deployment.yaml:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: ui
  namespace: client
spec:
  replicas: 1
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 2
  template:
    metadata:
      labels:
        app: ui
    spec:
      containers:
        - name: ui
          image: #######
          imagePullPolicy: IfNotPresent
          ports:
            - name: http
              containerPort: 80

Backend service.yaml:

apiVersion: v1
kind: Service
metadata:
  name: api
  namespace: client
  labels:
    app: api
spec:
  type: NodePort
  ports:
    - port: 8001
      protocol: TCP
      targetPort: http
      name: http
  selector:
    app: api

Backend deployment.yaml:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: api
  namespace: client
  labels:
    name: api
spec:
  replicas: 1
  revisionHistoryLimit: 2
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: api
    spec:
      containers:
        - name: api
          image: ####
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8001