How to Expose Single REST API in Kubernetes Cluster?

Admin May 17, 2023
How to Expose a Single REST API in Kubernetes to the Outside Cluster

This post will help you to understand different methods is to expose single REST API in Kubernetes Cluster to the outside world and will provide step by step instructions. Because this is one common requirement for us to expose single REST API to allow external access to specific services within Kubernetes Cluster.

If you are interested in learning, Request you to go through the below recommended tutorial.

Topics:

  1. Using NodePort Service

  2. Using LoadBalancer Service

  3. Using Ingress Controller

  4. Choosing the Right Method

  5. Step by Step Instructions

Using NodePort Service:

NodePort service type helps us to expose services on specific port on each node in kubernetes cluster. With this NodePort Service, Our service can be accessed from externally by using respective node's IP address and allocated port. This NodePort Service is a basic and straight inbuilt feature available in kubernetes cluster, But it may not best for realtime production scenarios as it requires managing port mappings manually.

Using LoadBalancer Service:

LoadBalancer service type is another feature that uses cloud provider and it supports external load balancers. Kubernetes will automatically create one loadbalancer and will assign one external IP address or CNAME record. This will route or forward the network traffic to the service. This Loadbalancer service method is more suitable for production realtime environments with high availability and automatic load balancing.

Using Ingress Controller:

Ingress controller is a additional controller to be installed on kubernetes cluster. This load balancer operates at the application layer (Layer 7) and it provides more advanced routing capabilities. It uses kubernetes ingress resources to define or create rules for routing incoming requests to different services based on paths, hostnames or patterns. This Ingress controller method is highly stuitable and it allows for sophisticated routing configurations on kubernetes cluster.

Choosing the Right Method:

When selecting right method to expose single REST API in Kubernetes cluster, consider the application, deployments and environment requirements. NodePort is the easiest and simple method but it doesnt have automation and scalability. LoadBalancer is a good option for cloud-based environemtn but may have additional costs involved. Ingress Controller is the most advanced features but it requires additional configuration and supported Ingress controller implementation.

Step by Step Instructions:

Let's see the step by step instructions for exposing single REST API using NodePort service type:

Step 1: Create Kubernetes deployment and service using Kubectl command:

$ kubectl create deployment my-api --image=my-api-image
$ kubectl expose deployment my-api --port=80 --target-port=8080 --type=NodePort

Step 2: Find NodePort IP assigned to service:

$ kubectl get service my-api

Step 3: Access REST API externally using node's IP address and NodePort number:

http://<node-ip>:<node-port>
That's it for this post. Keep practicing and have fun. Leave your comments if any.

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