Dockerized REST API with Spring and H2 Database

This Spring Sync REST API uses H2 database it uses in-memory database. Use this repo to dockerize and deploy it in Kubernetes for tutorial. You will need the JAR file which is located in root. Here are the commands to create an image and push it to Azure Container Registry and deploy it in Azure Kubernetes Service

Start with creating Docker image and container in your local machine first:

• docker build -t api:latest .
• docker run -it --rm -p 8081:8081 api:latest will have Docker running port 8081
• docker run -it --rm -p 8080:8081 api:latest will have Docker running port 8080 (8081 is the container to port and 8080 is the Docker host port)
• docker run -it --rm -p 80:8081 api:latest will have Docker running port 80
• Open up Postman and try http://localhost:8081/api/employees/
• Remove all docker images locally for /F %i in ('docker images -a -q') do docker rmi -f %i

GET ALL method http://localhost:8081/api/employees/

GET by id method http://localhost:8081/api/employees/1

POST method http://localhost:8081/api/employees/ and add the request body:

{
  "id" : "1",
  "name" : "nyadog",
  "salary" : "123"
}

PUT method http://localhost:8081/api/employees/1 and add the body

{
  "id" : "1",
  "name" : "nyanya",
  "salary" : "321"
}

DELETE method http://localhost:8081/api/employees/1

Push Docker image to Github as a package:

1. Generate Github PAT and tick upload packages
2. Open cmd
3. docker login -u $GITHUB_USERNAME -p $GITHUB_TOKEN docker.pkg.github.com
4. docker tag $IMAGE_ID docker.pkg.github.com/<user-name>/<repo-name>/<image-name>:<tag-name>
5. docker push docker.pkg.github.com/<user-name>/<repo-name>/<image-name>:<tag-name>

Push Docker image to Docker Hub

1. Open cmd
2. run docker build -t api:latest .
3. run docker login
4. run docker tag api:latest <your-docker-id>/<docker-repo-name>:<tag-it-with-whatever-name-you-want>

Example: docker tag api:latest bigtiddy/microservices-api-training:initial-push

5. docker push <your-docker-id>/<docker-repo-name>:<tag-it-with-whatever-name-you-want>

Example: docker push bigtiddy/microservices-api-training:initial-push

Push Docker image to ACR

Login:

• az acr login --name <registry-name>
• az aks get-credentials --resource-group <resource-group-name> --name <kubernetes-name>

Create deployment.yml and service.yml for Azure Kubernetes Service

kind: Deployment
metadata:
  name: <MY-DEPLOYMENT>
spec:
  selector:
    matchLabels:
      app: <MY-POD-MUST-MATCH>
  template:
    metadata:
      labels:
        app: <MY-POD-MUST-MATCH>
    spec:
      containers:
      - name: <MY-CONTAINER>
        image: <LOGIN-SERVER/REPO-NAME:TAG>
        resources:
          limits:
            memory: "128Mi"
            cpu: "500m"
        ports:
        - containerPort: 80

Service YAML template for people to access the pod in AKS

apiVersion: v1
kind: Service
metadata:
  name: <MY-SERVICE
spec:
  selector:
    app: <MY-POD-MUST-MATCH>
  ports:
  - port: 8080
    targetPort: <MUST MATCH containerPort> ex 80
  type: LoadBalancer

Creating image and pushing it to ACR and AKS:

• docker build -t image-name:tag .
• docker tag image-name:tag <login-server/reponame:tag>
• docker push <login-server/reponame:tag>
• kubectl apply -f .<deployment-file.yml>
• kubectl get deployment
• kubectl get pods

You should see the external IP and the port after you execute "kubectl get pods" type the IP and the port and test it with Postman http://external-ip:port/api/employees/

If you want to test the app locally, run the app and test it using Postman http://localhost:8080/api/employees/