Start the Docker daemon

On a Linux Docker Engine installation managed by systemd, start and inspect the service with:

sudo systemctl start docker
sudo systemctl status docker

Enable it at boot only if that matches the machine's role:

sudo systemctl enable docker.service

Then test the client and server with docker version or docker info. A daemon connection error can also come from the wrong Docker context or socket permissions, so check docker context show before starting random processes.

Docker Desktop on macOS and Windows manages its engine through the desktop application; start Docker Desktop rather than running dockerd manually. Rootless Docker has a different user service and must follow its own setup. Running dockerd by hand can create a second daemon with a different data directory and socket. If the service fails, read journalctl -u docker and fix the first configuration or storage error.

Sources

• Docker documentation
• Docker CLI reference