Kubernetes Ingress – The Smart Gateway to Your Applications

When you deploy applications on Kubernetes, one of the first real-world challenges you face is exposing your application to the outside world. Pods are isolated inside the cluster by default, and Kubernetes gives us multiple ways to make them accessible.

At first glance, using a LoadBalancer service feels like the easiest solution. But as your system grows, this approach quickly becomes expensive, rigid, and hard to manage.

This is where Kubernetes Ingress comes in a smarter, centralized, and production-ready way to manage external traffic.

So we will break down what Ingress is, why it exists, how it works internally, and why it’s the preferred solution in real-world Kubernetes setups, based on my recent learning.

The Core Problem: Accessing Applications from Outside the Cluster

The most common beginner-friendly solution is creating a Service of type LoadBalancer. This exposes the application using a cloud provider’s load balancer.

While this works, it comes with major drawbacks:

• High cost – Each service creates its own load balancer

• Cloud provider lock-in – Tightly coupled with AWS, GCP, Azure, etc.

• Limited routing & security features

In large systems with many services, this approach becomes inefficient and expensive.

This image clearly shows the “one load balancer per service” problem.

The Smarter Solution: Kubernetes Ingress

Ingress provides a centralized gateway for all incoming HTTP/HTTPS traffic because it operates at Layer 7 (application layer), enabling host-based and path-based routing, whereas Kubernetes Services operate at Layer 4 (transport layer) and route traffic only based on IP and port.

Instead of creating a load balancer for every service:

• You create one external load balancer

• Route traffic internally using Ingress rules

• Manage everything using declarative YAML

Ingress is an API object, not a load balancer itself. It defines how traffic should be routed.

The Three Pillars of the Ingress System

Ingress works because of three core components:

1. Ingress Controller

• The actual engine that handles traffic

• Examples: NGINX, Traefik, Kong, HAProxy

2. Ingress Resource

• A YAML file that defines routing rules

• Host-based and path-based routing

3. Service

• The backend destination for traffic

Without an Ingress Controller, the Ingress resource does nothing.

Understanding how traffic flows makes Ingress much easier to grasp.

Typical request flow:

• User sends an HTTP request

• Request hits the cloud load balancer

• Traffic reaches the Ingress Controller

• Controller checks Ingress rules

• Routes traffic to the correct Service

• Service forwards it to the Pod

Ingress allows routing traffic based on:

• Hostnames (example.com)

• Paths (/api, /app, /admin)

All this logic is defined declaratively in YAML, making it version-controlled and repeatable.

Installing an Ingress Controller

An Ingress resource alone does nothing.

You must install an Ingress Controller, such as:

• NGINX Ingress

• Traefik

• Kong

• Ambassador

Only then will Kubernetes start routing traffic based on your rules.

Critical Details on ingressClassName

When multiple Ingress Controllers exist in a cluster, Kubernetes needs to know which controller should handle which Ingress.

This is done using:

spec:
ingressClassName: nginx

Without this, routing conflicts and unexpected behavior can occur.