K8s Deployment Sample 1: Hello World Scenario

Let's define a basic Hello World scenario using ESB Micro Integrator and deploy it on your Kubernetes environment.

Prerequisites

Step 1 - Create the integration solution

Let's use an integration template in ESB Integration Studio to generate a sample integration solution that returns a 'Hello World' response when invoked.

  1. Open ESB Integration Studio.

  2. In the Getting Started view, select the Hello Kubernetes template.

    getting started view

  3. Give a project name and click Finish.

This generates the complete integration project with the 'Hello World' solution, which is ready to be deployed in Kubernetes.

k8s project structure

Step 2 - Build and Push the Docker image

Note

Be sure to start your Docker instance before building the image. If Docker is not started, the build process will fail.

There are two ways to build a Docker image of the integration solution and push it to your Docker registry:

  • Using Maven:

    Before you begin

    You need Maven 3.5.2 or a later version when you build the Docker image manually (without using ESB Integration Studio).

    1. Open a terminal and navigate to the integration project.

    2. Execute the following command.

      Be sure to specify the user name and password of the correct Docker registry.

      mvn clean install -Dmaven.test.skip=true -Ddockerfile.username={username} -Ddockerfile.password={password}

    This will build the Docker image and then push it to the specified Docker registry.

  • Using ESB Integration Studio:

    1. Open the pom.xml file in the Kubernetes project as shown below.

    2. Ensure that the composite exporter is selected under Dependencies.

    3. In the Target Repository field, enter the name of the Docker registry to which you will push a Docker image.
    4. Click Build & Push to build the image and push to the Docker registry.

    5. In the dialog box that opens, enter the credentials of your Docker registry to which the image should be pushed.

      docker registry credentials

    6. Click Push Image.

Run the docker image ls command to verify that the Docker image is created.

Step 3 - Deploy the solution in K8s

Info

Before you begin, the API Kubernetes Operator should be installed in your Kubernetes environment.

Follow the steps given below.

  1. Open the integration_cr.yaml file from the Kubernetes exporter in ESB Integration Studio.

  2. See that the integration details of the hello-world solution are updated. Be sure to add the image name in the following format: docker_user/repository:tag

    apiVersion: "wso2.com/v1alpha2"
kind: "Integration"
metadata:
  name: "hello-world"
spec:
  image: "<Docker image for the Hello World Scenario>"
  deploySpec:
    minReplicas: 1

  3. Open a terminal and start the Kubernetes cluster.

  4. Navigate to the location of your integration_cr.yaml file and execute the following command to deploy the integration solution in the Kubernetes cluster:

    kubectl apply -f integration_cr.yaml

When the integration is successfully deployed, it should create the hello-world integration, hello-world-deployment, hello-world-service, and ei-operator-ingress as follows:

Tip

The ei-operator-ingress is not created if you have disabled the ingress controller.

kubectl get integration

NAME          STATUS    SERVICE-NAME    AGE
hello-world   Running   hello-service   2m

kubectl get deployment

NAME                     READY   UP-TO-DATE   AVAILABLE   AGE
hello-world-deployment   1/1     1            1           2m

kubectl get services
NAME                     TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)       AGE
hello-world-service      ClusterIP   10.101.107.154   <none>        8290/TCP      2m
kubernetes               ClusterIP   10.96.0.1        <none>        443/TCP       2d
k8s-api-operator         ClusterIP   10.98.78.238     <none>        443/TCP       1d

kubectl get ingress
NAME                  HOSTS                      ADDRESS     PORTS     AGE
api-operator-ingress  wso2ei.ingress.wso2.com    10.0.2.15   80, 443   2m

Step 4 - Test the deployment

Let's invoke the service without going through the ingress controller.

  1. Apply port forwarding as shown below. This will allow you to invoke the service without going through the Ingress controller: 

    kubectl port-forward service/hello-world-service 8290:8290

  2. Invoke the service as follows: 

    curl http://localhost:8290/HelloWorld

You will receive the following response:

{"Hello":"World"}%
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