DOCKER_HOST was not set, couldn't be found in the usual loca

Error message

DOCKER_HOST was not set, couldn't be found in the usual locations, and the container daemon socket ('%s') is invalid

What it means

Error "DOCKER_HOST was not set, couldn't be found in the usual locations, and the container daemon socket ('%s') is invalid" thrown in nektos/act.

Source

Thrown at pkg/container/docker_socket.go:93

// Exit early if we're in an invalid state (e.g. when no DOCKER_HOST and user supplied "-", a dash or omitted)
if !hasDockerHost && socketHost.Socket != "" && !isDockerHostURI(socketHost.Socket) {
	// Cases: 1B, 2B
	// Should we early-exit here, since there is no host nor socket to talk to?
	return SocketAndHost{}, fmt.Errorf("DOCKER_HOST was not set, couldn't be found in the usual locations, and the container daemon socket ('%s') is invalid", socketHost.Socket)
}

View on GitHub (pinned to 4f41128141)

Solutions

Set DOCKER_HOST to a valid socket, e.g. unix:///var/run/docker.sock.
Start the Docker daemon and confirm /var/run/docker.sock exists.
On rootless Docker or Podman, point DOCKER_HOST at the user socket (e.g. unix:///run/user/$UID/docker.sock).

When it happens

Trigger: Thrown at pkg/container/docker_socket.go:93 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nektos/act@4f41128141 (2026-08-15). Data as JSON: /api/errors/5ba297d2807f0681. Report an issue: GitHub.