Create a Deployment for the Web Application

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web-app
  template:
    metadata:
      labels:
        app: web-app
    spec:
      containers:
        - name: web-app-container
          image: your-web-app-image:tag
          ports:
            - containerPort: 8080

Create a Service to Expose the Web Application

apiVersion: v1
kind: Service
metadata:
  name: web-app-service
spec:
  selector:
    app: web-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080
  type: LoadBalancer

Apply the Deployments and Service

kubectl apply -f web-app-deployment.yaml
kubectl apply -f web-app-service.yaml

Access the Exposed Web Application

kubectl get service web-app-service

Look for the "EXTERNAL-IP" field, which will provide the external IP address assigned to the Service. Open a web browser and enter the external IP address to access the web application.

Discovering Services and Pods using DNS

Discovering a Service using DNS

import socket

service_host = "my-service.default.svc.cluster.local"
service_port = 80

service_address = socket.gethostbyname(service_host)
print(f"Service IP: {service_address}")

Discovering a Pod using DNS

import socket

pod_host = "my-pod.default.pod.cluster.local"
pod_port = 8080

pod_address = socket.gethostbyname(pod_host)
print(f"Pod IP: {pod_address}")

Kubernetes API

from kubernetes import client, config

config.load_kube_config()
api_instance = client.CoreV1Api()

services = api_instance.list_service_for_all_namespaces().items
for service in services:
    print(f"Service Name: {service.metadata.name}")
    print(f"Service Namespace: {service.metadata.namespace}")
    print(f"Service IP: {service.spec.cluster_ip}")
    print("---")

Ingress

from kubernetes import client, config

config.load_kube_config()
api_instance = client.ExtensionsV1beta1Api()

ingresses = api_instance.list_ingress_for_all_namespaces().items
for ingress in ingresses:
    print(f"Ingress Name: {ingress.metadata.name}")
    print(f"Ingress Namespace: {ingress.metadata.namespace}")
    for rule in ingress.spec.rules:
        print(f"Host: {rule.host}")
        for path in rule.http.paths:
            print(f"Path: {path.path}")
            print(f"Service: {path.backend.service_name}")
            print(f"Service Port: {path.backend.service_port}")
            print("---")