Docker Compose with Nginx - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the Nginx image in the Docker Compose service.

Nginx

services:
  webserver:
    image: nginx[1]

Drag options to blanks, or click blank then click option'

A:dev

B:latest

C:alpine

D:stable

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the colon before the tag

Using a non-existent tag like ':dev'

The image field specifies which Nginx version to use. :stable is a common tag for a reliable version.

2fill in blank

medium

Complete the code to map port 8080 on the host to port 80 in the Nginx container.

Nginx

services:
  webserver:
    ports:
      - "[1]:80"

Drag options to blanks, or click blank then click option'

A8080

B80

C8000

D443

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the ports (e.g., '80:8080')

Using a port not allowed or already in use

Port mapping syntax is host_port:container_port. Here, host port 8080 maps to container port 80.

3fill in blank

hard

Fix the error in the volume mapping to serve a custom Nginx config file.

Nginx

services:
  webserver:
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf[1]

Drag options to blanks, or click blank then click option'

A:ro

B:rw

C::ro

D::rw

Attempts:

3 left

💡 Hint

Common Mistakes

Using double colons (::) which is invalid

Forgetting the read-only flag when needed

The volume mapping syntax uses a single colon : to separate host and container paths. :ro means read-only.

4fill in blank

hard

Fill both blanks to complete the environment variable and restart policy for the Nginx service.

Nginx

services:
  webserver:
    environment:
      - NGINX_HOST=[1]
    restart: [2]

Drag options to blanks, or click blank then click option'

Alocalhost

Balways

Con-failure

Dproduction

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid restart policies

Setting environment variables to wrong values

NGINX_HOST is set to localhost for local testing. The restart policy always restarts the container if it stops.

5fill in blank

hard

Fill all three blanks to complete the Docker Compose service with build context, Dockerfile, and network.

Nginx

services:
  webserver:
    build:
      context: [1]
      dockerfile: [2]
    networks:
      - [3]

Drag options to blanks, or click blank then click option'

A.

BDockerfile.nginx

Cfrontend

Dnginx

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong network names

Incorrect Dockerfile names or paths

The build context is the current directory .. The Dockerfile is named Dockerfile.nginx. The service connects to the frontend network.

Practice

1. What is the main purpose of using Docker Compose with Nginx?

easy

A. To replace Nginx with a different web server

B. To run Nginx and other services together easily using a YAML file

C. To write Nginx configuration files in JSON format

D. To compile Nginx from source code automatically

Solution

1. Step 1: Understand Docker Compose role

   Docker Compose helps run multiple services together using a simple YAML file.

2. Step 2: Connect with Nginx usage

   Using Docker Compose with Nginx lets you start Nginx and other needed services easily.

3. Final Answer:

   To run Nginx and other services together easily using a YAML file -> Option B

4. Quick Check:

   Docker Compose + Nginx = easy multi-service setup [OK]

Hint: Docker Compose uses YAML to run multiple services together [OK]

Common Mistakes:

• Thinking Docker Compose changes Nginx config format
• Confusing Docker Compose with Nginx replacement
• Assuming Docker Compose compiles software

2. Which of the following is the correct way to expose port 80 of an Nginx container in a Docker Compose file?

easy

A. publish: 80

B. expose: 80:80

C. ports: - "80:80"

D. port: 80

Solution

1. Step 1: Recall Docker Compose port syntax

   To expose ports, use the 'ports' key with format "hostPort:containerPort" as a list item.

2. Step 2: Match correct syntax

   Only 'ports: - "80:80"' correctly exposes container port 80 to host port 80.

3. Final Answer:

   ports: - "80:80" -> Option C

4. Quick Check:

   Expose ports with 'ports: - "host:container"' [OK]

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

Common Mistakes:

• Using 'expose' with port mapping syntax
• Writing 'port' instead of 'ports'
• Using 'publish' which is invalid in Compose

3. Given this Docker Compose snippet, what will happen when you run docker-compose up?

services:
  web:
    image: nginx:latest
    ports:
      - "8080:80"
    volumes:
      - ./site-content:/usr/share/nginx/html:ro

medium

A. Nginx will serve files from /usr/share/nginx/html on port 80 only

B. Nginx will serve default content on port 80

C. Nginx will fail to start due to volume error

D. Nginx will serve files from ./site-content on port 8080

Solution

1. Step 1: Analyze port mapping

   Port 8080 on host maps to port 80 in container, so access via localhost:8080.

2. Step 2: Analyze volume mapping

   Local folder './site-content' is mounted read-only to Nginx's html folder, so custom files are served.

3. Final Answer:

   Nginx will serve files from ./site-content on port 8080 -> Option D

4. Quick Check:

   Port 8080 mapped and volume mounted = custom site served [OK]

Hint: Check ports and volumes to predict container behavior [OK]

Common Mistakes:

• Ignoring port mapping and assuming port 80
• Assuming volume mount fails without error
• Confusing container and host ports

4. You wrote this Docker Compose service for Nginx but after running docker-compose up the container starts but you cannot access Nginx on port 80:

services:
  nginx:
    image: nginx
    ports:
      - "80"
    volumes:
      - ./html:/usr/share/nginx/html

What is the likely cause?

medium

A. Port mapping "80" maps a random host port to container 80; should be "80:80"

B. Volume path './html' does not exist

C. Image name 'nginx' is invalid

D. Missing environment variables for Nginx

Solution

1. Step 1: Check port mapping syntax

   "80" is valid short syntax mapping random host port to container port 80; to bind host port 80 use "80:80".

2. Step 2: Confirm other parts

   Volume path and image name are valid; environment variables are optional for basic Nginx.

3. Final Answer:

   Port mapping "80" maps a random host port to container 80; should be "80:80" -> Option A

4. Quick Check:

   Port mapping must be "hostPort:containerPort" [OK]

Hint: Port mapping needs both host and container ports separated by colon [OK]

Common Mistakes:

• Using single port number without colon
• Assuming volume path error without checking
• Thinking image name 'nginx' is wrong

5. You want to run Nginx with Docker Compose and add a custom configuration file nginx.conf located in your project folder. Which Docker Compose volume setting correctly mounts this file to override the default Nginx config at /etc/nginx/nginx.conf?

hard

A. - ./nginx.conf:/etc/nginx/nginx.conf:ro

B. - ./nginx.conf:/usr/share/nginx/html/nginx.conf

C. - /etc/nginx/nginx.conf:./nginx.conf

D. - ./nginx.conf:/etc/nginx/conf.d/nginx.conf

Solution

1. Step 1: Identify correct Nginx config path

   The main Nginx config file is at /etc/nginx/nginx.conf inside the container.

2. Step 2: Match volume mount syntax

   Mount local nginx.conf to container path with read-only flag ':ro' to override default config safely.

3. Final Answer:

   - ./nginx.conf:/etc/nginx/nginx.conf:ro -> Option A

4. Quick Check:

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

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

Common Mistakes:

• Mounting to wrong container path
• Reversing source and target paths
• Omitting ':ro' for config files