ClusterIP service Not accessible from within the cluster pods

Question

I have got 2 deployments in my cluster UI and USER. Both of these are exposed by Cluster IP service. There is an ingress which makes both the services publicly accessible.

Now when I do "kubectl exec -it UI-POD -- /bin/sh" and then try to "ping USER-SERVICE-CLUSTER-IP:PORT" it doesn't work.

All I get is No packet returned ie a failure message.

Attaching my .yml file

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service-app
  labels:
    app: user-service-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: user-service-app
  template:
    metadata:
      labels:
        app: user-service-app
    spec:
      containers:
      - name: user-service-app
        image: <MY-IMAGE-URL>
        imagePullPolicy: Always
        ports:
        - containerPort: 3000
        livenessProbe:
          httpGet:
            path: /ping
            port: 3000
        readinessProbe:
          httpGet:
            path: /ping
            port: 3000
          
          

---
apiVersion: "v1"
kind: "Service"
metadata:
  name: "user-service-svc"
  namespace: "default"
  labels:
    app: "user-service-app"
spec:
  type: "ClusterIP"
  selector:
    app: "user-service-app"
  ports:
  - protocol: "TCP"
    port: 80
    targetPort: 3000

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ui-service-app
  labels:
    app: ui-service-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ui-service-app
  template:
    metadata:
      labels:
        app: ui-service-app
    spec:
      containers:
      - name: ui-service-app
        image: <MY-IMAGE-URL>
        imagePullPolicy: Always
        ports:
        - containerPort: 3000

---
apiVersion: "v1"
kind: "Service"
metadata:
  name: "ui-service-svc"
  namespace: "default"
  labels:
    app: "ui-service-app"
spec:
  type: "ClusterIP"
  selector:
    app: "ui-service-app"
  ports:
  - protocol: "TCP"
    port: 80
    targetPort: 3000
  


---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: awesome-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  ingressClassName: nginx
  defaultBackend:
    service:
      name: ui-service-svc
      port:
        number: 80
  rules:
  - http:
      paths:      
      - path: /login
        pathType: Prefix
        backend:
          service:
            name: ui-service-svc
            port:
              number: 80
      - path: /user(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: user-service-svc
            port:
              number: 80

Answer 1

Ping operates by means of Internet Control Message Protocol (ICMP) packets. This is not what your service is serving. You can try curl USER-SERVICE-CLUSTER-IP/ping or curl http://user-service-svc/ping within your UI pod.