Introduction

• Like an entirely separate, independent machine.

• Run Kubernetes locally on local laptop by creating a single-node Kubernetes cluster.

  minikube start
  

• Check cluster

  kubectl get nodes
  

• Instead of using AWS/GCP, can:

  • Practice Kubernetes
  • Test deployments
  • Learn safely
  • Without paying cloud money

Install Minikube

• Prerequisites:
  • Install Docker Desktop
  • Enable WSL2 backend
  • Make sure Docker is running
• choco install minikube
• minikube version

Minikube runs inside a VM

• Minikube pods runs in isolated K8s network
• So in deploment.yaml should put host.docker.internal
  • To break out of container (vm), and go talk to the main host machine.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: springboot-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: springboot-app
  template:
    metadata:
      labels:
        app: springboot-app
    spec:
      containers:
        - name: app
          image: minhen/springboot-app:latest
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8088
          env:
            - name: SPRING_PROFILES_ACTIVE
              value: prod
            - name: SPRING_DATASOURCE_URL
              value: jdbc:postgresql://**host.docker.internal**:5435/mhpractice
            - name: SPRING_DATASOURCE_USERNAME
              value: minhen
            - name: SPRING_DATASOURCE_PASSWORD
              value: minhen
            - name: SPRING_DATA_REDIS_HOST
              value: **host.docker.internal**
            - name: SPRING_DATA_REDIS_PORT
              value: "6380"
            - name: SPRING_KAFKA_BOOTSTRAP_SERVERS
              value: host.docker.internal:9092
            - name: SPRING_KAFKA_CONSUMER_GROUP_ID
              value: wallet-service-group
            - name: JWT_SECRET
              value: dG9wLXNlY3JldC1rZXktZm9yLWp3dC1zaWduaW5nLTI1Ni1iaXQ=
            - name: JWT_ENCRYPTION_KEY
              value: MTIzNDU2Nzg5MDEyMzQ1Njc4OTAxMjM0NTY3ODkwMTI=
            - name: SPRING_MAIL_HOST
              value: **host.docker.internal**
            - name: SPRING_MAIL_PORT
              value: "1026"

Use Minikube + kubectl

1. Start Minikube (start the vm that act as Kubernetes cluster):

   minikube start
   

2. Load the app image in Minikube

   1. Since Minikube is separated (doesn't share a hard drive with local machine).
   2. Copy springboot-app:1.0 Docker image (contains whole app jar and Java runtime) from local machine into Minikube's internal hard drive.
   3. So the cluster can access it later.

   minikube image load springboot-app:1.0