Expert’s Guide to Deploy a Micronaut Microservices Application to Oracle Cloud Infrastructure Container Engine for Kubernetes

This guide describes how to deploy a Micronaut® application, consisting of three microservices, to the Oracle Cloud Infrastructure Container Engine for Kubernetes (OKE) using the Micronaut Kubernetes project.

The Micronaut Kubernetes project provides integration between Micronaut and Kubernetes. It adds support for the following features:

  • Service Discovery
  • Configuration client for config maps and secrets
  • Kubernetes blocking and non-blocking clients built on top of the official Kubernetes Java SDK

OKE is a managed Kubernetes service for deploying containerized applications to the cloud.

The guide demonstrates how to use Kubernetes Service Discovery and Distributed Configuration to connect three microservices, and discover how Micronaut integration with Kubernetes simplifies deployment to OKE.

Note: The guide assumes that the reader is familiar with using the Oracle Cloud Infrastructure Command Line Interface (CLI).

The application consists of three microservices:

  • users - contains customer data that can place orders on items, also a new customer can be created. It requires HTTP basic authentication to access it.
  • orders - contains all orders that customers have created as well as available items that customers can order. This microservice also enables the creation of new orders. It requires HTTP basic authentication to access it.
  • api - acts as a gateway to the orders and users microservices. It combines results from both microservices and checks data when a customer creates a new order.

Prerequisites #

A note regarding your development environment

Consider using Visual Studio Code that provides native support for developing applications with the Graal Development Kit extension.

Note: If you use IntelliJ IDEA, enable annotation processing.

Windows platform: The GDK guides are compatible with Gradle only. Maven support is coming soon.

1. Create or Download a Microservices Application #

You can create a microservices application from scratch by following this guide, or you can download the completed example:

The application ZIP file will be downloaded in your default downloads directory. Unzip it and proceed to the next steps.

Note: By default, a Micronaut application detects its runtime environment. A detected environment (in this case, k8s) overrides the default specified environment (in this case, oraclecloud). This means that you should locate your configuration in the application-k8s.properties and bootstrap-k8s.properties files. Alternatively, you can specify the oraclecloud environment passing it as a command-line option (-Dmicronaut.environments=oraclecloud) or via an environment variable (MICRONAUT_ENVIRONMENTS=oraclecloud).

2. Create an Oracle Cloud Infrastructure Kubernetes Cluster #

You will use Quick Create cluster option in OKE to create Kubernetes cluster.

  1. Login to the Oracle Cloud console and open the navigation menu. Click Developer Services. Under Containers & Artifacts, click Kubernetes Clusters (OKE).
  2. Choose your compartment in the Compartment drop-down list.
  3. Click Create cluster and choose the Quick create option and click Submit.
  4. Enter the name for your cluster, for example, gdk-k8s. Select Public Endpoint for the Kubernetes API endpoint; Private Workers for worker nodes; and the shape (choose the default). Click Next.
  5. Click Create cluster.
  6. It may take a few minutes to create all the resources. When they are all complete, click Close.
  7. From the Cluster details tab click Copy to copy the Cluster Id (you will need it later).

3. Prepare to Deploy Microservices #

3.1. Export Environment Variables #

Define some environment variables to make deploying process easier:

  • OCI_USER_ID to store your user OCID, which you can find in your Oracle Cloud Infrastructure configuration file (usually ~/.oci/config).
  • OCI_TENANCY_NAMESPACE to store the tenancy namespace (retrieve your tenancy namespace using the Oracle Cloud Infrastructure CLI).
  • OCIR_USERNAME store your username in the format <tenancy_namespace>/<username>. You can reuse OCI_TENANCY_NAMESPACE and only edit the <username> part.
  • OCI_REGION to store your cloud region identifier, for example, “us-phoenix-1”.
  • OCI_CLUSTER_ID to store the Cluster Id that you copied earlier.
  • OCI_COMPARTMENT_ID to store your compartment id.

For example:

export OCI_USER_ID="ocid1.user.oc1..aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
export OCI_TENANCY_NAMESPACE=$(oci os ns get | jq .data -r)
export OCIR_USERNAME="$OCI_TENANCY_NAMESPACE/<username>"
export OCI_REGION="<region>"
export OCI_CLUSTER_ID="ocid1.cluster.oc1.iad.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
export OCI_COMPARTMENT_ID="ocid1.compartment.oc1..aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
The export command syntax varies per platform. Expand to learn more.

If you use Windows, change export to set if using the cmd prompt:

set OCI_USER_ID=<id>

If you use PowerShell, change export to $ and use quotes around the value, for example:

$OCI_USER_ID="<id>"

To dereference a value in Linux/macOS or PowerShell, use $, for example: /some/command -option=$OCI_USER_ID

If you use cmd, use % before and after the name, for example: /some/command -option=%OCI_USER_ID%

3.2. Authenticate to Oracle Cloud Infrastructure Registry #

  1. Create an AUTH_TOKEN to authenticate to Oracle Cloud Infrastructure Registry (also known as Container Registry). (Oracle Cloud Infrastructure allows you to have only two authentication tokens at the same time. If you already have two, use the existing one or delete the one that you are not using.)

  2. Export the AUTH_TOKEN variable:
     export AUTH_TOKEN=$(oci iam auth-token create --user-id $OCI_USER_ID --description gdk-k8s-token | jq -r '.data.token')
    
  3. Run the next command to log in to ocir.io (Container Registry):
     docker login $OCI_REGION.ocir.io -u $OCIR_USERNAME -p $AUTH_TOKEN
    

    The command should complete by printing “Login Succeeded”. (It may take some time before your authentication token activates.)

3.3. Create and Publish a Container Image of the Native Users Microservice #

To create a container image of the native users microservice named “users”, run the following command from the users/ directory:

./gradlew dockerBuildNative

Note: If you encounter problems creating a container image, run the following command from the users/build/docker/native-main/ directory:

docker build . -t users-oci -f DockerfileNative
./mvnw clean package -Dpackaging=docker-native -Pgraalvm

Note: If you encounter problems creating a container image, run the following command from the users/target/ directory:

docker build . -t users-oci -f Dockerfile

Note: Ensure that you construct container images for the correct CPU architecture. For instance, if you are using AArch64, modify the DOCKER_DEFAULT_PLATFORM environment variable to the value linux/amd64. Alternatively, you have the option to use AArch64 instances within your Kubernetes cluster.

3.4. Create a Container Repository for the Users Microservice #

Your next step is to prepare a container repository in Container Registry.

  1. Create a Container Repository named “gdk-k8s/users-oci” in your compartment:

     export USERS_REPOSITORY=$(oci artifacts container repository create --display-name gdk-k8s/users-oci --compartment-id $OCI_COMPARTMENT_ID | jq .data.id -r)
    
  2. Tag the existing users microservice container image with details of the container repository:

     docker tag users-oci:latest $OCI_REGION.ocir.io/$OCI_TENANCY_NAMESPACE/gdk-k8s/users-oci:latest
    
  3. Push the tagged users microservice container image to the remote repository:

     docker push $OCI_REGION.ocir.io/$OCI_TENANCY_NAMESPACE/gdk-k8s/users-oci:latest
    

3.5. Update the Users Microservice #

Edit the file named users/k8s-oci.yml as follows:

apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: gdk-k8s
  name: users
spec:
  selector:
    matchLabels:
      app: users
  template:
    metadata:
      labels:
        app: users
    spec:
      serviceAccountName: gdk-service
      containers:
        - name: users
          image: '<region>.ocir.io/<tenancy-namespace>/gdk-k8s/users-oci:latest' # <1>
          imagePullPolicy: Always # <2>
          ports:
            - name: http
              containerPort: 8080
          readinessProbe:
            httpGet:
              path: /health/readiness
              port: 8080
            initialDelaySeconds: 5
            timeoutSeconds: 3
          livenessProbe:
            httpGet:
              path: /health/liveness
              port: 8080
            initialDelaySeconds: 5
            timeoutSeconds: 3
            failureThreshold: 10
          env:
            - name: MICRONAUT_ENVIRONMENTS
              value: oraclecloud
      imagePullSecrets:
        - name: ocirsecret # <3>
---
apiVersion: v1
kind: Service
metadata:
  namespace: gdk-k8s
  name: users
spec:
  selector:
    app: users
  type: NodePort
  ports:
    - protocol: TCP
      port: 8080

1 The tag of the container image in Container Registry. Change the <region> to your region and replace <tenancy-namespace> with your tenancy namespace. (This MUST match the tag you created above in step 2 of section 3.4.)

2 The imagePullPolicy is Always, which means that Kubernetes will always pull the latest version of the image from the container registry.

3 The name of a secret to pull container images from Container Registry. (You will create the secret in section 4.)

3.6. Create and Publish a Container Image of the Native Orders Microservice #

To create a container image of the native orders microservice named “orders”, run the following command from the orders/ directory:

./gradlew dockerBuildNative

Note: If you encounter problems creating a container image, run the following command from the orders/build/docker/native-main/ directory:

docker build . -t orders-oci -f DockerfileNative
./mvnw clean package -Dpackaging=docker-native -Pgraalvm

Note: If you encounter problems creating a container image, run the following command from the orders/target/ directory:

docker build . -t orders-oci -f Dockerfile

Note: Ensure that you construct container images for the correct CPU architecture. For instance, if you are using AArch64, modify the DOCKER_DEFAULT_PLATFORM environment variable to the value linux/amd64. Alternatively, you have the option to use AArch64 instances within your Kubernetes cluster.

3.7. Create a Container Repository for the Orders Microservice #

  1. Create a container repository named “gdk-k8s/orders-oci” in your compartment.

     export ORDERS_REPOSITORY=$(oci artifacts container repository create --display-name gdk-k8s/orders-oci --compartment-id $OCI_COMPARTMENT_ID | jq .data.id -r)
    
  2. Tag the existing orders microservice container image with details of the container repository:

     docker tag orders-oci:latest $OCI_REGION.ocir.io/$OCI_TENANCY_NAMESPACE/gdk-k8s/orders-oci:latest
    
  3. Push the tagged orders microservice container image to the remote repository:

     docker push $OCI_REGION.ocir.io/$OCI_TENANCY_NAMESPACE/gdk-k8s/orders-oci:latest
    

3.8. Update the Orders Microservice #

Edit the file named orders/k8s-oci.yml as follows:

apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: gdk-k8s
  name: orders
spec:
  selector:
    matchLabels:
      app: orders
  template:
    metadata:
      labels:
        app: orders
    spec:
      serviceAccountName: gdk-service
      containers:
        - name: orders
          image: '<region>.ocir.io/<tenancy-namespace>/gdk-k8s/orders-oci:latest' # <1>
          imagePullPolicy: Always # <2>
          ports:
            - name: http
              containerPort: 8080
          readinessProbe:
            httpGet:
              path: /health/readiness
              port: 8080
            initialDelaySeconds: 5
            timeoutSeconds: 3
          livenessProbe:
            httpGet:
              path: /health/liveness
              port: 8080
            initialDelaySeconds: 5
            timeoutSeconds: 3
            failureThreshold: 10
          env:
            - name: MICRONAUT_ENVIRONMENTS
              value: oraclecloud
      imagePullSecrets:
        - name: ocirsecret # <3>
---
apiVersion: v1
kind: Service
metadata:
  namespace: gdk-k8s
  name: orders
spec:
  selector:
    app: orders
  type: NodePort
  ports:
    - protocol: TCP
      port: 8080

1 The container image tag that exists in Container Registry. Change the <region> to your region and replace <tenancy-namespace> with your tenancy namespace. (This MUST match the tag you created above in step 2 of section 3.7.)

2 Change imagePullPolicy to Always, which means that Kubernetes will always pull the latest version of the image from the container registry.

3 The name of a secret to pull container images from Container Registry. (You will create the secret in section 4.)

3.9. Create and Publish a Container Image of the Native API (Gateway) Microservice #

To create a container image of the native api microservice named “api”, run the following command from the api/ directory:

./gradlew dockerBuildNative

Note: If you encounter problems creating a container image, run the following command from the api/build/docker/native-main/ directory:

docker build . -t api-oci -f DockerfileNative
./mvnw clean package -Dpackaging=docker-native -Pgraalvm

Note: If you encounter problems creating a container image, run the following command from the api/target/ directory:

docker build . -t api-oci -f Dockerfile

Note: Ensure that you construct container images for the correct CPU architecture. For instance, if you are using AArch64, modify the DOCKER_DEFAULT_PLATFORM environment variable to the value linux/amd64. Alternatively, you have the option to use AArch64 instances within your Kubernetes cluster.

3.10. Create a Container Repository for the API Microservice #

  1. Create a container repository named “gdk-k8s/api-oci” in your compartment:

     export API_REPOSITORY=$(oci artifacts container repository create --display-name gdk-k8s/api-oci --compartment-id $OCI_COMPARTMENT_ID | jq .data.id -r)
    
  2. Tag the existing api microservice container image with details of the container repository:

     docker tag api-oci:latest $OCI_REGION.ocir.io/$OCI_TENANCY_NAMESPACE/gdk-k8s/api-oci:latest
    
  3. Push the tagged api microservice container image to the remote repository:

     docker push $OCI_REGION.ocir.io/$OCI_TENANCY_NAMESPACE/gdk-k8s/api-oci:latest
    

3.11. Update the API Microservice #

Edit the file named api/k8s-oci.yml as follows:

apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: gdk-k8s
  name: api
spec:
  selector:
    matchLabels:
      app: api
  template:
    metadata:
      labels:
        app: api
    spec:
      serviceAccountName: gdk-service
      containers:
        - name: api
          image: '<region>.ocir.io/<tenancy-namespace>/gdk-k8s/api-oci:latest' # <1>
          imagePullPolicy: Always # <2>
          ports:
            - name: http
              containerPort: 8080
          readinessProbe:
            httpGet:
              path: /health/readiness
              port: 8080
            initialDelaySeconds: 5
            timeoutSeconds: 3
          livenessProbe:
            httpGet:
              path: /health/liveness
              port: 8080
            initialDelaySeconds: 5
            timeoutSeconds: 3
            failureThreshold: 10
          env:
            - name: MICRONAUT_ENVIRONMENTS
              value: oraclecloud
      imagePullSecrets:
        - name: ocirsecret # <3>
---
apiVersion: v1
kind: Service
metadata:
  namespace: gdk-k8s
  name: api
  annotations: # <4>
    oci.oraclecloud.com/load-balancer-type: lb
    service.beta.kubernetes.io/oci-load-balancer-shape: flexible
    service.beta.kubernetes.io/oci-load-balancer-shape-flex-min: '10'
    service.beta.kubernetes.io/oci-load-balancer-shape-flex-max: '10'
spec:
  selector:
    app: api
  type: LoadBalancer
  ports:
    - protocol: TCP
      port: 8080

1 The container image name that exists in Container Registry. Change the <region> to your region and replace <tenancy-namespace> with your tenancy namespace. (This MUST match the tag you created above in step 2 of section 3.10.)

2 Change imagePullPolicy to Always, which means that Kubernetes will always pull the latest version of the image from the container registry.

3 The name of a secret to pull container images from Container Registry. (You will create the secret in section 4.)

4 Metadata annotations for an Oracle Cloud Infrastructure Load Balancer.

4. Deploy Microservices to OKE #

  1. Create a directory for a kubectl configuration:

     mkdir -p $HOME/.kube
    
  2. Generate a kubectl configuration for authentication to OKE:

     oci ce cluster create-kubeconfig \
           --cluster-id $OCI_CLUSTER_ID \
           --file $HOME/.kube/config \
           --region $OCI_REGION \
           --token-version 2.0.0 \
           --kube-endpoint PUBLIC_ENDPOINT
    
  3. Set KUBECONFIG to the created config file, as shown below. (This variable is consumed by kubectl.)

     export KUBECONFIG=$HOME/.kube/config
    

    Note: On Windows, kubectl is typically installed within the Kubernetes extension and is not added to the system path. Windows users should configure a proxy in .kube/config to successfully deploy a project to Oracle Cloud Infrastructure: add a proxy-url property under cluster.

     clusters:
     - name: "dev"
       cluster:
         proxy-url: http://user:password@proxy:port
         ...
    
  4. Deploy the auth.yml file that you created in the Deploy a Micronaut Microservices Application to a Local Kubernetes Cluster guide:

     kubectl apply -f auth.yml
    
  5. Create an ocirsecret secret for authentication to Container Registry using the command below. The secret is a object to store user credential data (encrypted data), for example, the database username and password. In this case, OKE uses it to authenticate to Container Registry to be able to pull microservices container images.

     kubectl create secret docker-registry ocirsecret \
           --docker-server=$OCI_REGION.ocir.io \
           --docker-username=$OCIR_USERNAME \
           --docker-password=$AUTH_TOKEN \
           --namespace=gdk-k8s
    
  6. Deploy the users microservice:

     kubectl apply -f users/k8s-oci.yml
    
  7. Deploy the orders microservice:

     kubectl apply -f orders/k8s-oci.yml
    
  8. Run the next command to deploy the api microservice:

     kubectl apply -f api/k8s-oci.yml
    

5. Test Integration Between the Microservices Deployed to OKE #

  1. Run the following command to check the status of the pods and make sure that all of them have the status “Running”:
     kubectl get pods -n=gdk-k8s
    
     NAME                      READY   STATUS    RESTARTS   AGE
     api-6fb4cd949f-kxxx8      1/1     Running   0          13s
     orders-595887ddd6-6lzp4   1/1     Running   0          25s
     users-df6f78cd7-lgnzx     1/1     Running   0          37s
  2. Run this command to check the status of the microservices:

     kubectl get services -n=gdk-k8s
    
     NAME         TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)             AGE
     api          LoadBalancer   10.96.70.48    129.146.149.81   8080:31666/TCP      2m9s
     orders       NodePort       10.96.94.130   <none>           8080:31702/TCP      2m22s
     users        NodePort       10.96.34.174   <none>           8080:31528/TCP      2m33s

    If EXTERNAL-IP is in a <pending> state, wait a few seconds and then run the command again.

  3. Retrieve the URL of the api microservice and set it as the value of the $API_URL environment variable:

     export API_URL=http://$(kubectl get svc api -n=gdk-k8s -o json | jq -r '.status.loadBalancer.ingress[0].ip'):8080
    
  4. Run a curl command to create a new user via the api microservice:

     curl -X "POST" "$API_URL/api/users" \
          -H 'Content-Type: application/json; charset=utf-8' \
          -d '{ "first_name": "Nemanja", "last_name": "Mikic", "username": "nmikic" }'
    

    Your output should look like:

     {
       "id":1,
       "username":"nmikic",
       "first_name":"Nemanja",
       "last_name":"Mikic"
     }
    
  5. Run a curl command to create a new order via the api microservice:

     curl -X "POST" "$API_URL/api/orders" \
          -H 'Content-Type: application/json; charset=utf-8' \
          -d '{ "user_id": 1, "item_ids": [1,2] }'
    

    Your output should include details of the order, as follows:

     {
       "id": 1,
       "user": {
         "first_name": "Nemanja",
         "last_name": "Mikic",
         "id": 1,
         "username": "nmikic"
       },
       "items": [
         {
           "id": 1,
           "name": "Banana",
           "price": 1.5
         },
         {
           "id": 2,
           "name": "Kiwi",
           "price": 2.5
         }
       ],
       "total": 4.0
     }
    
  6. Run a curl command to list the orders:

     curl "$API_URL/api/orders" \
          -H 'Content-Type: application/json; charset=utf-8'
    

    You should see output that is similar to the following:

     [
       {
         "id": 1,
         "user": {
           "first_name": "Nemanja",
           "last_name": "Mikic",
           "id": 1,
           "username": "nmikic"
         },
         "items": [
           {
             "id": 1,
             "name": "Banana",
             "price": 1.5
           },
           {
             "id": 2,
             "name": "Kiwi",
             "price": 2.5
           }
         ],
         "total": 4.0
       }
     ]
    
  7. Try to place an order for a user who does not exist (with id 100). Run a curl command:

     curl -X "POST" "$API_URL/api/orders" \
          -H 'Content-Type: application/json; charset=utf-8' \
          -d '{ "user_id": 100, "item_ids": [1,2] }'
    

    You should see the following error message:

     {
       "message": "Bad Request",
       "_links": {
         "self": [
           {
             "href": "/api/orders",
             "templated": false
           }
         ]
       },
       "_embedded": {
         "errors": [
           {
             "message": "User with id 100 doesn't exist"
           }
         ]
       }
     }
    

6. Clean Up Cloud Resources #

After you have finished this guide, clean up the resources you created.

  1. Delete all Kubernetes resources that were created in this guide:

     kubectl delete namespaces gdk-k8s
    
  2. Delete the OKE cluster:

     oci ce cluster delete --cluster-id $OCI_CLUSTER_ID --force
    
  3. Delete the gdk-k8s/users-oci artifacts container repository:

     oci artifacts container repository delete --repository-id $USERS_REPOSITORY --force
    
  4. Delete the gdk-k8s/order-oci artifacts container repository:

     oci artifacts container repository delete --repository-id $ORDERS_REPOSITORY --force
    
  5. Delete the gdk-k8s/api-oci artifacts container repository:

     oci artifacts container repository delete --repository-id $API_REPOSITORY --force
    

Summary #

This guide demonstrated how to use Kubernetes Service Discovery and Distributed Configuration, provided with the Micronaut Kubernetes integration, to connect three microservices, and to deploy these microservices to a Kubernetes cluster in Oracle Cloud Infrastructure Container Engine for Kubernetes.