Official Nginx Docker image - Mini Project: Build & Apply

Using the Official Nginx Docker Image

📖 Scenario: You want to quickly set up a simple web server to serve a static website using Docker. Nginx is a popular web server, and the official Nginx Docker image makes it easy to run Nginx inside a container.This project will guide you step-by-step to create a Docker container running Nginx, serve a simple HTML page, and verify it works.

🎯 Goal: Build a Docker container using the official Nginx image that serves a custom HTML page on your local machine.

📋 What You'll Learn

Create a basic HTML file named index.html with specific content

Write a Dockerfile that uses the official nginx:latest image

Copy the index.html file into the correct Nginx directory inside the container

Build and run the Docker container exposing port 8080

Verify the web page is served correctly by printing the curl command output

💡 Why This Matters

🌍 Real World

Developers and system administrators often use the official Nginx Docker image to quickly deploy web servers for testing or production.

💼 Career

Knowing how to use official Docker images like Nginx is a key skill for DevOps roles, enabling fast and consistent deployment of web services.

1

Create the HTML file

Create a file named index.html with the exact content: <h1>Welcome to My Nginx Server</h1>

Nginx

# Create index.html file with the required content
# Your code here

Hint

Use a text editor to create index.html with the heading inside.

2

Write the Dockerfile

Create a file named Dockerfile with these exact lines:
FROM nginx:latest
COPY index.html /usr/share/nginx/html/index.html

Nginx

# Write Dockerfile with FROM and COPY commands
# Your code here

Hint

The Dockerfile must start with FROM nginx:latest and copy index.html to the Nginx html folder.

3

Build and run the Docker container

Run these exact commands in your terminal:
docker build -t my-nginx .
docker run -d -p 8080:80 --name webserver my-nginx

Nginx

# Build and run the Docker container with the given commands
# Your code here

Hint

Use docker build to create the image and docker run to start the container on port 8080.

4

Verify the Nginx server is running

Run the command curl http://localhost:8080 and print its output exactly.

Nginx

# Run curl command and print output
# Your code here

Hint

Use curl http://localhost:8080 in your terminal to see the page content.

Practice

1. What is the primary purpose of the official Nginx Docker image?

easy

A. To quickly run Nginx inside a container for web serving

B. To build custom Linux kernels

C. To manage databases inside containers

D. To create virtual machines

Solution

1. Step 1: Understand the role of Nginx

   Nginx is a web server used to serve websites and handle web traffic.

2. Step 2: Recognize the Docker image purpose

   The official Nginx Docker image allows running Nginx easily inside containers for web serving.

3. Final Answer:

   To quickly run Nginx inside a container for web serving -> Option A

4. Quick Check:

   Official Nginx Docker image = Quick Nginx container [OK]

Hint: Nginx image runs web server in container fast [OK]

Common Mistakes:

• Confusing Nginx with database or VM tools
• Thinking it builds Linux kernels
• Assuming it manages virtual machines

2. Which Docker command correctly runs the official Nginx image exposing port 80 on the host?

easy

A. docker run -p 80 nginx

B. docker run -p 8080:80 nginx

C. docker run -p 80:80 nginx

D. docker run nginx -p 80:80

Solution

1. Step 1: Understand Docker port mapping syntax

   The correct syntax is docker run -p hostPort:containerPort image.

2. Step 2: Match the command to expose port 80 on host

   docker run -p 80:80 nginx uses -p 80:80 which maps host port 80 to container port 80 correctly.

3. Final Answer:

   docker run -p 80:80 nginx -> Option C

4. Quick Check:

   Port mapping syntax = -p hostPort:containerPort [OK]

Hint: Use -p hostPort:containerPort to expose ports [OK]

Common Mistakes:

• Omitting container port in -p option
• Placing -p after image name
• Using wrong port numbers

3. What will be the result of running this command?

docker run --rm -p 8080:80 nginx

Then accessing http://localhost:8080 in a browser?

medium

A. Connection refused error

B. You will see the default Nginx welcome page

C. 404 Not Found error

D. Docker container will fail to start

Solution

1. Step 1: Analyze the Docker run command

   The command runs Nginx container mapping host port 8080 to container port 80, with --rm to remove container after exit.

2. Step 2: Understand Nginx default behavior

   Nginx serves a default welcome page on port 80 if no custom config is provided.

3. Final Answer:

   You will see the default Nginx welcome page -> Option B

4. Quick Check:

   Default Nginx page served on mapped port [OK]

Hint: Default Nginx page shows if no config mounted [OK]

Common Mistakes:

• Expecting 404 without custom config
• Thinking container fails without volumes
• Confusing port 80 with 8080 inside container

4. You tried to run:

docker run -p 80:80 nginx

but got an error: port is already allocated. What is the best fix?

medium

A. Stop the process using port 80 or use a different host port

B. Change the container port to 8080

C. Remove the Nginx image and pull again

D. Run the container without port mapping

Solution

1. Step 1: Understand the error meaning

   "port is already allocated" means host port 80 is in use by another process.

2. Step 2: Choose a fix for port conflict

   Stopping the process using port 80 or mapping to a different host port avoids conflict.

3. Final Answer:

   Stop the process using port 80 or use a different host port -> Option A

4. Quick Check:

   Port conflict fix = stop process or change host port [OK]

Hint: Port conflict means host port busy; change or free it [OK]

Common Mistakes:

• Changing container port instead of host port
• Deleting image won't fix port conflict
• Running without port mapping disables access

5. You want to customize Nginx by using your own nginx.conf file located at /home/user/nginx.conf. Which Docker command correctly mounts this config into the container?

hard

A. docker run -v /etc/nginx/nginx.conf:/home/user/nginx.conf -p 8080:80 nginx

B. docker run -v /home/user/nginx.conf:/usr/local/nginx/nginx.conf -p 8080:80 nginx

C. docker run -v /home/user/nginx.conf:/etc/nginx/conf.d/nginx.conf -p 8080:80 nginx

D. docker run -v /home/user/nginx.conf:/etc/nginx/nginx.conf:ro -p 8080:80 nginx

Solution

1. Step 1: Identify correct Nginx config path inside container

   The main config file path in official Nginx image is /etc/nginx/nginx.conf.

2. Step 2: Use volume mount syntax to map host config

   Mount host file /home/user/nginx.conf to container path /etc/nginx/nginx.conf with read-only flag :ro.

3. Final Answer:

   docker run -v /home/user/nginx.conf:/etc/nginx/nginx.conf:ro -p 8080:80 nginx -> Option D

4. Quick Check:

   Mount host config to /etc/nginx/nginx.conf with :ro [OK]

Hint: Mount config to /etc/nginx/nginx.conf with :ro for safety [OK]

Common Mistakes:

• Reversing source and target paths in -v option
• Mounting to wrong container config directory
• Omitting :ro to prevent accidental changes