Warning: stopping docker.service, but it can still be activated by: docker.socket

Explanation:

When you see the warning message “stopping docker.service, but it can still be activated by: docker.socket,” it means that although the Docker service is being stopped, it can still be activated through the Docker socket.

The Docker service is responsible for managing and running Docker containers. It provides an interface for interacting with the containers and ensures they are properly started, stopped, and managed.

However, Docker can also be managed and controlled through its socket. The Docker socket is a communication endpoint that allows you to interact with the Docker service outside the regular service management. It provides a secure way to interact with the Docker daemon.

By default, Docker is configured to start the service when a request is made via the socket, even if the service itself was stopped previously. This is designed to ensure that Docker remains accessible and can quickly start serving containers.

Let’s consider an example:

$ sudo systemctl stop docker.service
$ systemctl status docker.service

The output of the second command will display the warning message “stopping docker.service, but it can still be activated by: docker.socket.” This means that although the Docker service is stopped, it can still be activated by making a request via the Docker socket.

However, if you want to prevent the Docker service from being activated even through the socket, you can disable the socket unit as well:

$ sudo systemctl stop docker.service
$ sudo systemctl stop docker.socket
$ systemctl status docker.service

In this case, the Docker service will no longer be accessible, even if a request is made via the Docker socket. It ensures that Docker remains completely stopped until explicitly started again.