What is Docker and what is Docker daemon?

Docker is a platform for developing, shipping, and running applications in containers.

Containers allow packaging an application with all its dependencies into an isolated environment, ensuring predictability and portability.

Docker daemon (or dockerd) is a background service that manages all Docker operations. It is responsible for:

• Building, starting, and stopping containers.
• Managing images.
• Managing data volumes.
• Managing networks.
• Handling requests from the Docker CLI (Client).

The client (for example, the docker build or docker run command) interacts with the Docker daemon via API.

# Example of a Docker CLI command sending a request to the Docker daemon
docker run -d -p 80:80 nginx