Custom config in Docker in Nginx - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of using a custom configuration file in a Docker container running nginx?

A custom configuration file allows you to change nginx settings like server names, ports, or root directories without modifying the container image itself.

beginner

How do you include a custom nginx config file in a Docker container?

You can mount the custom config file into the container using a volume with the -v option in docker run, for example: docker run -v /my/custom/nginx.conf:/etc/nginx/nginx.conf nginx

beginner

What is the default location of the nginx main configuration file inside the official nginx Docker container?

The default main configuration file is located at /etc/nginx/nginx.conf inside the container.

intermediate

Why is it better to use a volume mount for custom config instead of building a new Docker image?

Using a volume mount lets you change the config quickly without rebuilding the image. It keeps your workflow simple and flexible.

beginner

What command would you use to start an nginx container with a custom config file located at /home/user/nginx.conf on your host?

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

Where should you mount your custom nginx config file inside the container?

A /etc/nginx/nginx.conf

B /usr/local/nginx.conf

C /var/www/html/nginx.conf

D /home/nginx/nginx.conf

The official nginx Docker image uses /etc/nginx/nginx.conf as the main config file location.

What Docker option allows you to use your own config file without rebuilding the image?

A -d (detached mode)

B -v (volume mount)

C -p (port mapping)

D -e (environment variable)

The -v option mounts a file or directory from the host into the container, allowing custom configs.

If your custom config file has errors, what will happen when nginx starts in the container?

A The container will restart endlessly

B nginx will ignore errors and start normally

C Docker will automatically fix the config

D nginx will fail to start and show an error

nginx validates the config on start and will fail if there are syntax errors.

Which command maps port 8080 on your host to port 80 in the nginx container?

A -p 8080:80

B -p 80:8080

C -v 8080:80

D -e 8080=80

The -p option maps host port 8080 to container port 80.

Why add ':ro' at the end of a volume mount for the config file?

A To rename the file inside the container

B To make the file writable inside the container

C To make the file read-only inside the container

D To remove the file after container stops

Adding ':ro' makes the mounted file read-only, preventing accidental changes.

Explain how to use a custom nginx configuration file with Docker without rebuilding the image.

Think about how Docker volumes work and where nginx expects its config.

Describe the benefits of using a volume mount for nginx config in Docker compared to building a new image.

Consider how changing files on the host affects the container.