Prerequisites

Before we dive into the configuration steps, let’s make sure we have the following prerequisites in place:

1. A running Kubernetes cluster with a Java app deployed.
2. A registered domain name.
3. Access to your domain registrar’s DNS management settings.

Step 1: Obtain the External IP of the Ingress Controller

To configure a custom domain, we first need to obtain the external IP of the Ingress Controller. The Ingress Controller manages incoming traffic to your Kubernetes cluster.

1. Run the following command to get the external IP of the Ingress Controller:

kubectl get service <ingress-controller-service-name> -n <ingress-controller-namespace> -o jsonpath='{.status.loadBalancer.ingress[0].ip}'

Replace <ingress-controller-service-name> with the name of your Ingress Controller service and <ingress-controller-namespace> with the namespace where it is deployed.

Step 2: Configure DNS for Custom Domain

Once we have the external IP of the Ingress Controller, we can configure the DNS settings for our custom domain.

1. Log in to your domain registrar and navigate to the DNS management settings for your domain.
2. Create a new DNS record of type A (Address) for your custom domain.
3. In the Value or Points to field, enter the external IP of the Ingress Controller obtained in step 1.
4. Save the DNS record and wait for the changes to propagate. This process may take some time, usually a few hours.

Step 3: Update Ingress Resource

Now that the DNS is configured, we need to update the Ingress resource for our Java app.

1. Open the Ingress resource YAML file for your app.
2. Set the host field under the spec section to your custom domain name. For example:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
spec:
  rules:
    - host: **custom-domain.com**
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: myapp-service
                port:
                  number: 8080

Replace **custom-domain.com** with your actual domain name.

1. Apply the updated Ingress resource using the following command:

kubectl apply -f <ingress-resource-file.yaml>

Step 4: Verify Custom Domain Configuration

To verify if the custom domain configuration is successful, follow these steps:

1. Wait for the changes in DNS propagation.
2. Open a web browser and navigate to your custom domain (**custom-domain.com**).
3. If everything is correctly configured, you should see your Java app running on the custom domain.

Congratulations! You have successfully configured and managed a custom domain for your Java app running on Kubernetes.

Conclusion

Configuring and managing custom domains for Java apps on Kubernetes is essential for providing a professional experience to your users. By following the steps outlined in this blog post, you can easily set up custom domains and ensure your Java app is easily accessible under your desired domain name.

#java #Kubernetes