Services with YAML ¶

Step-01: Introduction to Services ¶

We are going to look in to below two services in detail with a frotnend and backend example
NodePort Service
ClusterIP Service

Kubernetes Manifests ¶

01-backend-deployment.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: backend-restapp
  labels: 
    app: backend-restapp
    tier: backend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: backend-restapp
  template: 
    metadata:
      labels:
        app: backend-restapp
        tier: backend
    spec:
      containers:
        - name: backend-restapp
          image: stacksimplify/kube-helloworld:1.0.0
          ports:
            - containerPort: 8080

02-backend-clusterip-service.yml

apiVersion: v1
kind: Service
metadata:
  name: my-backend-service ## VERY VERY IMPORTANT - NGINX PROXYPASS needs this name
  labels: 
    app: backend-restapp
    tier: backend
spec:
  #type: Cluster IP is a default service
  selector:
    app: backend-restapp
  ports: 
    - name: http
      port: 8080 # ClusterIp Service Port
      targetPort: 8080 # Container Port

03-frontend-deployment.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: frontend-nginxapp
  labels: 
    app: frontend-nginxapp
    tier: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: frontend-nginxapp
  template: 
    metadata:
      labels:
        app: frontend-nginxapp
        tier: frontend
    spec:
      containers:
        - name: frontend-nginxapp
          image: stacksimplify/kube-frontend-nginx:1.0.0
          ports:
            - containerPort: 80

04-frontend-nodeport-service.yml

apiVersion: v1
kind: Service
metadata:
  name: frontend-nginxapp-nodeport-service
  labels: 
    app: frontend-nginxapp
    tier: frontend     
spec:
  type: NodePort 
  selector:
    app: frontend-nginxapp
  ports: 
    - name: http
      port: 80
      targetPort: 80
      nodePort: 31234

Step-02: Create Backend Deployment & Cluster IP Service ¶

Write the Deployment template for backend REST application.
Write the Cluster IP service template for backend REST application.
Important Notes:
Name of Cluster IP service should be name: my-backend-service because same is configured in frontend nginx reverse proxy default.conf.

Test with different name and understand the issue we face

cd <Course-Repo>\kubernetes-fundamentals\10-Services-with-YAML\kube-manifests
kubectl get all
kubectl apply -f 01-backend-deployment.yml -f 02-backend-clusterip-service.yml
kubectl get all

Step-03: Create Frontend Deployment & NodePort Service ¶

Write the Deployment template for frontend Nginx Application

Write the NodePort service template for frontend Nginx Application

cd <Course-Repo>\kubernetes-fundamentals\10-Services-with-YAML\kube-manifests
kubectl get all
kubectl apply -f 03-frontend-deployment.yml -f 04-frontend-nodeport-service.yml
kubectl get all

Access REST Application

# Get External IP of nodes using
kubectl get nodes -o wide

# Access REST Application  (Port is static 31234 configured in frontend service template)
http://<node1-public-ip>:31234/hello

AWS EKS - Elastic Kubernetes Service - Masterclass ¶

Step-04: Delete & Recreate Objects using kubectl apply ¶

Delete Objects (file by file) ¶

kubectl delete -f 01-backend-deployment.yml -f 02-backend-clusterip-service.yml -f 03-frontend-deployment.yml -f 04-frontend-nodeport-service.yml
kubectl get all

Recreate Objects using YAML files in a folder ¶

cd <Course-Repo>\kubernetes-fundamentals\10-Services-with-YAML
kubectl apply -f kube-manifests/
kubectl get all

Delete Objects using YAML files in folder ¶

cd <Course-Repo>\kubernetes-fundamentals\10-Services-with-YAML
kubectl delete -f kube-manifests/
kubectl get all

Additional References - Use Label Selectors for get and delete ¶

https://kubernetes.io/docs/concepts/cluster-administration/manage-deployment/#using-labels-effectively
https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors