🌐 Exposing Applications Using Ingress (Beginner Friendly)

So far, our application is running inside the Kubernetes cluster and is accessible only internally using a Service (ClusterIP).

But as a fresher, the big question is:

❓ How do users access my application from a browser?

That’s where Ingress comes in.

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🤔 What Is Ingress in Kubernetes?

Ingress is a Kubernetes resource that:

• Exposes HTTP/HTTPS routes

• Acts as a smart entry point to your cluster

• Routes traffic to services based on URL paths or domains

Think of Ingress as:

🧠 A traffic controller sitting in front of your services

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🆚 Service vs Ingress (Simple Comparison)

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🏗️ How Ingress Works (Beginner Flow)

Browser
  ↓
Ingress Controller (NGINX / ALB)
  ↓
Ingress Rules
  ↓
Service
  ↓
Pod

📌 Important Note:
Ingress does not work alone.
You must install an Ingress Controller (like NGINX or AWS ALB).

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🧩 Ingress Controller (One-Time Setup)

For learning & labs, most beginners use NGINX Ingress Controller.

Example (one-time install):

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/cloud/deploy.yaml

⚠️ This is similar to how Argo CD provides an install.yaml.

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📝 Ingress YAML (Add to Same Single File)

Add this at the bottom of your myapp-install.yaml:

---
# =========================
# 11. Ingress
# =========================
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  namespace: myapp
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

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🔍 Ingress YAML Explained (Fresher View)

🔹 ingressClassName

ingressClassName: nginx

📌 Tells Kubernetes which ingress controller to use.

---

🔹 Host

host: myapp.example.com

📌 Domain name used to access the application.

For local testing:

sudo nano /etc/hosts
<Ingress-IP> myapp.example.com

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🔹 Path Routing

path: /
pathType: Prefix

📌 Routes all traffic starting with / to the service.

---

🔹 Backend Service

service:
  name: myapp-service
  port:
    number: 80

📌 Ingress never talks to Pods directly
It always routes traffic via a Service.

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🔐 HTTPS & TLS (Beginner Awareness)

Ingress can also:

• Enable HTTPS

• Use TLS certificates

• Integrate with cert-manager

(This is usually asked in interviews 👀)

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🚀 Accessing the Application

After applying:

kubectl apply -f myapp-install.yaml

Check ingress:

kubectl get ingress -n myapp

Open in browser:

http://myapp.example.com

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🧠 Interview Tip (Very Important)

Ingress vs LoadBalancer Service

✔ Service (LoadBalancer) → Exposes one service
✔ Ingress → Exposes multiple services using one IP

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🎯 Why Freshers Should Learn Ingress Early

• Used in real production

• Mandatory for microservices

• Required for Argo CD, EKS, AKS, GKE

• Common interview topic

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🏁 Final Takeaway

If you now understand:

• Service

• Ingress

• Ingress Controller

👉 You are already ahead of many beginners in Kubernetes.

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💬 Question for You

Do you want a real EKS Ingress setup using AWS ALB or NGINX Ingress deep dive next?