When beginners open a project repository, they often see files like:

ingress.yaml

or:

my-app-ingress.yml

and immediately get confused:

🤔 What is ingress?
🤔 Why do we need it?
🤔 What does this file do?
🤔 Is it mandatory?
🤔 What happens if we don’t use it?

If you are completely new to:

• Kubernetes
• DevOps
• deployments
• infrastructure

don’t worry.

This guide explains everything in a very simple way with real-world examples.

First Understand the Problem

Imagine you built a React or Node.js application.

Now you deployed it inside Kubernetes.

Question:

🤔 How will users access your application from the internet?

Because Kubernetes containers are running internally.

Users outside cannot directly access them.

This is where:

Ingress

comes into the picture.

What is Ingress?

Ingress is:

A way to expose your application to the outside world.

In simple words:

👉 It helps internet users access your application.

Real-World Analogy

Imagine:

• Your application = a house
• Kubernetes cluster = a big apartment building
• Users = visitors

Without ingress:

❌ Visitors don’t know:

• where to go
• which room belongs to which application

Ingress acts like:

security guard + receptionist

It:

• receives requests
• checks the URL
• sends users to correct application

What is an Ingress File?

An ingress file is usually:

ingress.yaml

It contains rules that tell Kubernetes:

• which domain should go where
• which route should open which service
• how incoming traffic should be handled

Example Ingress File

apiVersion: networking.k8s.io/v1kind: Ingressmetadata:  name: my-app-ingressspec:  rules:    - host: myapp.com      http:        paths:          - path: /            pathType: Prefix            backend:              service:                name: my-app-service                port:                  number: 80

What This File Means

This says:

If user visits myapp.com,send request to my-app-service

What Problem Does Ingress Solve?

Without ingress:

every application may need:

• separate public IP
• separate load balancer
• direct exposure

This becomes:

• expensive
• difficult to manage
• hard to scale

Ingress Solves This

Ingress provides:

• centralized routing
• domain-based routing
• path-based routing
• SSL handling
• traffic management

Real Example

Suppose you have:

Ingress can route all these properly.

Without Ingress

You may need:

3 separate load balancers3 public IPs

With Ingress

One ingress handles everything.

How Request Flows

Request Flow

User opens website        ↓Ingress receives request        ↓Checks rules        ↓Forwards request to correct service        ↓Application responds

Important Thing to Understand

Ingress does NOT directly connect to pods.

Flow is:

Ingress → Service → Pods

Beginner-Friendly Architecture

Internet User      ↓Ingress      ↓Kubernetes Service      ↓Pods/Containers

What is a Service?

A service is another Kubernetes component that:

• connects to pods
• provides stable networking

Ingress talks to services.

Services talk to pods.

Why We Need Ingress

✅ 1. Domain Routing

Example:

myapp.comapi.myapp.comadmin.myapp.com

✅ 2. Path Routing

Example:

/api/admin/profile

✅ 3. SSL/HTTPS Support

Ingress can handle:

HTTPSTLSSSL certificates

✅ 4. Centralized Traffic Management

One place to manage all traffic.

✅ 5. Cost Reduction

Instead of many load balancers:
👉 one ingress can handle multiple apps.

What Happens If We Don’t Use Ingress?

Your app may still work.

BUT:

you may need:

• NodePort
• LoadBalancer service
• direct exposure

Problems Without Ingress

❌ More Public IPs Needed

❌ More Expensive

Cloud load balancers cost money.

❌ Harder Traffic Management

❌ Difficult SSL Handling

❌ Difficult Multi-App Routing

Difference Between Service and Ingress

What is Ingress Controller?

This is VERY important.

Ingress file alone does nothing.

You also need:

Ingress Controller

What Does It Do?

It actually:

• reads ingress rules
• handles traffic
• applies routing

Popular Ingress Controllers

• NGINX Ingress Controller
• Traefik
• HAProxy
• AWS ALB Ingress Controller

Without Ingress Controller

Ingress file exists…

BUT:

❌ routing will NOT work.

Real Beginner Confusion

Many beginners think:

Creating ingress.yaml is enough

❌ Wrong.

You also need:

• ingress controller installed

Example Real Repository Structure

project/ ├── src/ ├── deployment.yaml ├── service.yaml ├── ingress.yaml

Why YAML Files?

Kubernetes uses YAML files to define infrastructure.

These files describe:

• deployments
• services
• ingress rules
• volumes
• configs

Important Kubernetes Files

Simple Full Flow

Full Architecture

User  ↓Ingress  ↓Service  ↓Pod  ↓Application

Best Practices

✅ Use Ingress for Production Apps

✅ Use HTTPS

Always secure traffic.

✅ Organize Routes Clearly

✅ Use One Ingress for Multiple Apps

Saves cost.

Common Beginner Mistakes

❌ Forgetting Ingress Controller

Most common issue.

❌ Wrong Service Name

Ingress routes fail.

❌ Wrong Port Number

Traffic not forwarded properly.

❌ DNS Not Configured

Domain won’t work.

Final Summary

✔ Ingress exposes applications to internet users
✔ It routes traffic to correct services
✔ Helps manage domains and paths
✔ Reduces infrastructure complexity
✔ Requires an ingress controller to work
✔ Commonly defined using ingress.yaml file

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