What is the role of the Docker daemon?

The Docker daemon (dockerd) is the core component of the Docker engine, responsible for managing Docker containers and images, and providing an interface for interaction with the Docker client.

The main role of a watchdog process includes:

1. Container management: the daemon is responsible for creating, starting, stopping, deleting, and managing Docker containers. It monitors the running status of containers and automatically adjusts as needed.
2. Image management: The daemon is responsible for downloading, uploading, building, and managing Docker images. It retrieves images from Docker Hub or other image repositories, and stores and manages them locally.
3. Resource management: The watchdog process is responsible for allocating and managing resources for containers, such as CPU, memory, and network. It can limit the amount of resources used by containers to ensure system stability and security.
4. Security management: The watchdog process is responsible for protecting the security of the container and Docker engine. It provides security features such as namespace isolation, resource limitations, and user permission management to ensure isolation and protection between containers.
5. Log and monitoring: A daemon is responsible for collecting and managing the logs and monitoring data of containers. It captures the output logs of containers and provides monitoring metrics such as CPU usage, memory usage, and network traffic.

In conclusion, the Docker daemon is the core of the Docker engine, responsible for managing containers and images, providing a range of functionalities and interfaces to make using and managing Docker easier and more efficient.