/k8s-spring-boot-example

Kubernetes Spring Boot Example commands

Kubernetes Spring Boot Example in Google Kubernetes Engine (GKE)

Table of Contents

Create Spring Boot app

You can use the sample project which I have in here.

git clone https://github.com/TechPrimers/spring-boot-lazy-init-example.git

Create Docker image

Command to create docker image using Google JIB plugin

./mvnw com.google.cloud.tools:jib-maven-plugin:build -Dimage=gcr.io/$GOOGLE_CLOUD_PROJECT/spring-boot-example:v1

Run the Docker image

Command to run the docker image which we created in the previous step

docker run -ti --rm -p 8080:8080 gcr.io/$GOOGLE_CLOUD_PROJECT/spring-boot-example:v1

Login to the K8s Cluster

Command to login to the K8s cluster from Cloud Shell

gcloud container clusters get-credentials techprimer-cluster-1 --zone us-central1-a

Kubernetes Commands

List Pods

kubectl get pods

List Deployments

kubectl get deployments

List Services

kubectl get services

Deploy an image

kubectl run spring-boot-example --image=gcr.io/$GOOGLE_CLOUD_PROJECT/spring-boot-example:v1 --port=8080

Expose Load Balancer

kubectl expose deployment spring-boot-example --type=LoadBalancer

Scale deployments

kubectl scale deployment spring-boot-example --replicas=3

K8s YAML Creator

Link to Brandon Potter's YML builder - https://static.brandonpotter.com/kubernetes/DeploymentBuilder.html

Deployment YML used

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: spring-boot-example
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v1'
          ports:
            - containerPort: 8080

Service YML used

apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
  type: LoadBalancer

Commands to Create/Update

  • kubectl apply -f deployment.yml
  • kubectl apply -f service.yml

Command to retrieve logs

kubectl logs <POD_NAME>

  • Pod Name can be retrived using kubectl get pods

Deployment Strategies

  • Recreate
  • RollingUpdate
  • Blue/Green
  • Canary

Recreate Strategy

kube.yml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example
spec:
  replicas: 3
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: spring-boot-example
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v1'
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
  type: LoadBalancer

Rolling Update Strategy

kube.yml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v1'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
---
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
  type: LoadBalancer

Blue Green Deployment

  • deployment-blue-v1.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example-v1
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
        version: "v1"
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v1'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
  • service-blue-v1.yml
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
    version: "v1"
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
    version: "v1"
  type: LoadBalancer
  • deployment-green-v2.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example-v2
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
        version: "v2"
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v2'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
  • service-green-v2.yml
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example-green
  labels:
    name: spring-boot-example-green
    version: "v2"
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
    version: "v2"
  type: LoadBalancer
  • deployment-blue-v2.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example-v2
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
        version: "v2"
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v2'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
  • service-blue-v2.yml
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
    version: "v2"
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
    version: "v2"
  type: LoadBalancer

Commands

  • kubectl apply -f deployment-blue-v1.yml
  • kubectl apply -f service-blue-v1.yml
  • kubectl apply -f deployment-green-v2.yml
  • kubectl apply -f service-green-v2.yml
  • kubectl apply -f deployment-blue-v2.yml
  • kubectl apply -f service-blue-v2.yml
  • kubectl delete deployment.apps/spring-boot-example-v1 service/spring-boot-example-green

Canary Deployments

Type 1

Using Tags in Kubernetes

  • kube-v1.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example-v1
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
        version: "v1"
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v1'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
---
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
    version: "v1"
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
    version: "v1"
  type: LoadBalancer
  • deployment-v2.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example-v2
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
        version: "v2"
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v2'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
  • Update Service to remove "version" tag. service-v1.yml
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
  type: LoadBalancer
  • add "v2" for version in the Service object service-v2.yml
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example
  labels:
    name: spring-boot-example
    version: "v2"
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
    version: "v2"
  type: LoadBalancer

Commands

  • kubectl apply -f kube-v1.yml
  • kubectl apply -f deployment-v2.yml
  • `kubectl apply -f service-v1.yml
  • `kubectl apply -f service-v2.yml

Type 2

  • Create V3 version along with Service object kube-v3.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: spring-boot-example-v3
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app: spring-boot-example
        version: "v1"
    spec:
      containers:
        - name: spring-boot-example
          image: 'gcr.io/fleet-resolver-237016/spring-boot-example:v3'
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /v3/lazy
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
---
apiVersion: v1
kind: Service
metadata:
  name: spring-boot-example-v3
  labels:
    name: spring-boot-example
    version: "v3"
spec:
  ports:
    - port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: spring-boot-example
    version: "v3"
  type: LoadBalancer
  • Ingress config ingress.yml
kind: Ingress
apiVersion: extensions/v1beta1
metadata:
  name: sb-ingress
spec:
  rules:
  - http:
      paths:
      - path: /lazy/*
        backend:
          serviceName: spring-boot-example
          servicePort: 8080
      - path: /v3/lazy
        backend:
          serviceName: spring-boot-example-v3
          servicePort: 8080
  • Remove and make default backend rule in ingress ingress-default.yml
kind: Ingress
apiVersion: extensions/v1beta1
metadata:
  name: sb-ingress
spec:
  backend:
    serviceName: spring-boot-example-v3
    servicePort: 8080

Commands

  • kubectl apply -f kube-v3.yml
  • kubectl apply -f ingress.yml
  • kubectl apply -f ingress-default.yml