Containerization-and-DevOps

Deploying NGINX Using Different Base Images and Comparing Image Layers

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Lab Objectives

After completing this lab, students will be able to:

• Deploy NGINX using:

  • Official nginx image
  • Ubuntu-based image
  • Alpine-based image
• Understand Docker image layers and size differences
• Compare performance, security, and use-cases of each approach
• Explain real-world use of NGINX in containerized systems

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Prerequisites

• Docker installed and running

• Basic knowledge of:

  • docker run
  • Dockerfile
  • Port mapping
• Linux command basics

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Part 1: Deploy NGINX Using Official Image (Recommended Approach)

Step 1: Pull the Image

docker pull nginx:latest

Step 2: Run the Container

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

Step 3: Verify

curl http://localhost:8080

You should see the NGINX welcome page.

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Key Observations

docker images nginx

• Image is pre-optimized
• Minimal configuration required
• Uses Debian-based OS internally

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Part 2: Custom NGINX Using Ubuntu Base Image

Step 1: Create Dockerfile

FROM ubuntu:22.04

RUN apt-get update && \
    apt-get install -y nginx && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*

EXPOSE 80

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

Step 2: Build Image

docker build -t nginx-ubuntu .

Step 3: Run Container

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

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Observations

docker images nginx-ubuntu

• Much larger image size
• More layers
• Full OS utilities available

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Part 3: Custom NGINX Using Alpine Base Image

Step 1: Create Dockerfile

FROM alpine:latest

RUN apk add --no-cache nginx

EXPOSE 80

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

Step 2: Build Image

docker build -t nginx-alpine .

Step 3: Run Container

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

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Observations

docker images nginx-alpine

• Extremely small image
• Fewer packages
• Faster pull and startup time

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Part 4: Image Size and Layer Comparison

Compare Sizes

docker images | grep nginx

Typical result (approx):

Image Type	Size
nginx:latest	~140 MB
nginx-ubuntu	~220+ MB
nginx-alpine	~25–30 MB

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Observations:

• Ubuntu has many filesystem layers
• Alpine has minimal layers
• Official NGINX image is optimized but heavier than Alpine

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Part 5: Functional Tasks Using NGINX

Task 1: Serve Custom HTML Page

mkdir html
echo "<h1>Hello from Docker NGINX</h1>" > html/index.html

Run:

docker run -d \
  -p 8083:80 \
  -v $(pwd)/html:/usr/share/nginx/html \
  nginx

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