Why containerized Nginx simplifies deployment - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start an Nginx container using Docker.

Nginx

docker run -d -p 80:80 [1]

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

Anode

Bapache

Cmysql

Dnginx

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong image name like apache or mysql.

Forgetting to map port 80.

The nginx image runs the Nginx web server inside a container. This command starts it detached and maps port 80.

2fill in blank

medium

Complete the command to remove a running Nginx container named 'webserver'.

Nginx

docker rm -f [1]

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

Awebserver

Bnginx

Ccontainer1

Dserver

Attempts:

3 left

💡 Hint

Common Mistakes

Using the image name instead of container name.

Using a generic name not matching the container.

The docker rm -f command forcefully stops and removes the container named webserver.

3fill in blank

hard

Fix the error in the Dockerfile line to copy the Nginx config file.

Nginx

COPY [1] /etc/nginx/nginx.conf

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

Adefault.conf

Bconfig.yaml

Cnginx.conf

Dindex.html

Attempts:

3 left

💡 Hint

Common Mistakes

Using unrelated files like index.html or config.yaml.

Using default.conf which is for site configs, not main config.

The Nginx main config file is named nginx.conf. Copying this file replaces the default configuration.

4fill in blank

hard

Fill both blanks to create a Docker command that runs Nginx with a custom config file from the host.

Nginx

docker run -d -p 8080:80 -v [1]:/etc/nginx/nginx.conf [2]

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

A/home/user/nginx.conf

Bnginx

C/etc/nginx/nginx.conf

Dapache

Attempts:

3 left

💡 Hint

Common Mistakes

Mounting the wrong file path.

Using the wrong image name like apache.

The -v option mounts the host's /home/user/nginx.conf file into the container's config path. The image used is nginx.

5fill in blank

hard

Fill all three blanks to write a Docker Compose service for Nginx exposing port 80 and using a volume for config.

Nginx

services:
  web:
    image: [1]
    ports:
      - "[2]:80"
    volumes:
      - [3]:/etc/nginx/nginx.conf

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

Anginx

B8080

C/home/user/nginx.conf

Dmysql

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong image names like mysql.

Incorrect port mapping.

Wrong volume paths.

This Docker Compose snippet runs the nginx image, maps host port 8080 to container port 80, and mounts the host config file /home/user/nginx.conf inside the container.

Practice

1. Why does using a containerized Nginx simplify deployment compared to installing Nginx directly on a server?

easy

A. Because it cannot be updated without reinstalling the server

B. Because it requires manual installation of dependencies on every server

C. Because it needs a specific operating system to work

D. Because it packages Nginx and its settings together, making it easy to run anywhere

Solution

1. Step 1: Understand container packaging

   Containerized Nginx bundles the server software and its configuration into one package.

2. Step 2: Recognize deployment benefits

   This bundle can run on any system with a container engine, avoiding manual setup each time.

3. Final Answer:

   Because it packages Nginx and its settings together, making it easy to run anywhere -> Option D

4. Quick Check:

   Container bundles = easy deployment [OK]

Hint: Think of container as a ready-to-go box for Nginx [OK]

Common Mistakes:

• Assuming container needs OS-specific setup
• Thinking container requires manual dependency installs
• Believing containerized apps can't be updated easily

2. Which of the following is the correct Docker command to run an Nginx container mapping port 8080 on the host to port 80 in the container?

easy

A. docker run -p 8080:80 nginx

B. docker run -p 80:8080 nginx

C. docker run -p 80 nginx

D. docker run nginx -p 8080:80

Solution

1. Step 1: Understand port mapping syntax

   The Docker -p option uses hostPort:containerPort format.

2. Step 2: Apply to Nginx ports

   Nginx listens on port 80 inside the container, so host port 8080 maps to container port 80.

3. Final Answer:

   docker run -p 8080:80 nginx -> Option A

4. Quick Check:

   HostPort:ContainerPort = 8080:80 [OK]

Hint: Remember Docker port mapping is host:container [OK]

Common Mistakes:

• Reversing port numbers in mapping
• Omitting container port in -p option
• Placing -p option after image name

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

docker run -d -p 8080:80 nginx

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

medium

A. The default Nginx welcome page will be shown

B. Connection refused error because port 80 is not exposed

C. 404 Not Found error because no content is served

D. Docker command will fail due to missing volume

Solution

1. Step 1: Analyze the Docker run command

   The command runs Nginx detached with port 8080 on host mapped to port 80 in container.

2. Step 2: Understand Nginx default behavior

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

3. Final Answer:

   The default Nginx welcome page will be shown -> Option A

4. Quick Check:

   Port mapped + default page = welcome page [OK]

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

Common Mistakes:

• Assuming port 80 is not exposed by default
• Expecting 404 without custom content
• Thinking volume is mandatory to run Nginx container

4. You tried to run Nginx in a container with:

docker run -d -p 80:80 nginx

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

medium

A. Remove the -d option to run in foreground

B. Reinstall Docker to fix port allocation

C. Change the host port mapping to a free port like 8080

D. Use docker run nginx without port mapping

Solution

1. Step 1: Understand the error cause

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

2. Step 2: Fix by changing host port

   Mapping to a free port like 8080 avoids conflict and allows container to start.

3. Final Answer:

   Change the host port mapping to a free port like 8080 -> Option C

4. Quick Check:

   Port conflict fix = change host port [OK]

Hint: Pick a free host port to avoid conflicts [OK]

Common Mistakes:

• Removing -d does not fix port conflicts
• Reinstalling Docker is unnecessary
• Running without port mapping means no external access

5. You want to customize Nginx configuration inside a container without rebuilding the image. Which approach best simplifies deployment?

hard

A. Run Nginx without any config to use defaults

B. Use a Docker volume to mount your custom config file into the container

C. Rebuild the Nginx image with your config baked in

D. Edit the Nginx config inside the running container directly

Solution

1. Step 1: Understand container immutability

   Containers are usually immutable; editing inside is temporary and lost on restart.

2. Step 2: Use volumes for config customization

   Mounting a config file via a volume lets you change settings without rebuilding the image.

3. Final Answer:

   Use a Docker volume to mount your custom config file into the container -> Option B

4. Quick Check:

   Volumes = easy config updates without rebuild [OK]

Hint: Mount config files with volumes to avoid rebuilds [OK]

Common Mistakes:

• Editing inside container is lost after restart
• Rebuilding image is slower and less flexible
• Running without config ignores needed custom settings