DevOps-Containerization

NGINX Docker Image Comparison Lab

A hands-on DevOps lab demonstrating how different base images impact Docker image size, performance, security, and layers using NGINX.

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Project Objective

This project explores:

• Deploying NGINX using the official image
• Building custom NGINX images using Ubuntu and Alpine
• Understanding Docker image layers
• Comparing performance, size, and security implications

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Project Structure

nginx-docker-lab/
│
├── nginx-ubuntu/
│   └── Dockerfile
│
├── nginx-alpine/
│   └── Dockerfile
│
└── README.md

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Part 1 — Run Official NGINX Image

Pull Image

docker pull nginx:latest

Run Container

docker run -d --name nginx-official -p 8080:80 nginx

Verify

Open:

http://localhost:8080

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Part 2 — Build NGINX Using Ubuntu Base

Dockerfile

FROM ubuntu:22.04

RUN apt update && apt install -y nginx

EXPOSE 80

CMD ["nginx", "-g", "daemon off;"]

Build

docker build -t nginx-ubuntu .

Run

docker run -d --name nginx-ubuntu -p 8081:80 nginx-ubuntu

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Part 3 — Build NGINX Using Alpine Base

Dockerfile

FROM alpine:3.19

RUN apk add --no-cache nginx

EXPOSE 80

CMD ["nginx", "-g", "daemon off;"]

Build

docker build -t nginx-alpine .

Run

docker run -d --name nginx-alpine -p 8082:80 nginx-alpine

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Image Size Comparison

docker images

Image	Base OS	Approx Size
nginx	Official	Medium
nginx-ubuntu	Ubuntu	Large
nginx-alpine	Alpine	Small

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Inspect Image Layers

docker history nginx
docker history nginx-ubuntu
docker history nginx-alpine

Each Dockerfile command creates a new layer. More OS packages = larger layers.

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Performance & Security Comparison

Feature	Official	Ubuntu	Alpine
Size	Medium	Large	Small
Security	Good	More attack surface	Minimal
Speed	Fast	Moderate	Fastest
Use Case	Default	Full OS apps	Cloud-native apps

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Conclusion

This lab proves that base image selection significantly affects Docker image size, security posture, and deployment efficiency. Alpine-based images are ideal for microservices and cloud environments, while Ubuntu provides flexibility for complex applications. Official images offer a balanced, production-ready setup.

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Cleanup

docker stop nginx-official nginx-ubuntu nginx-alpine
docker rm nginx-official nginx-ubuntu nginx-alpine

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Built for learning DevOps, Containers, and Cloud-Native best practices.

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