Check if Docker is running

pkg/cluster/cluster.go

@@ -341,6 +341,9 @@ func (c *Cluster) Create() error {
 	if err := c.ensureSSHKey(); err != nil {
 		return err
 	}
+	if err := docker.IsRunning(); err != nil {
+		return err
+	}
 	for _, template := range c.spec.Machines {
 		if _, err := docker.PullIfNotPresent(template.Spec.Image, 2); err != nil {
 			return err
@@ -384,11 +387,17 @@ func (c *Cluster) DeleteMachine(machine *Machine, i int) error {
 
 // Delete deletes the cluster.
 func (c *Cluster) Delete() error {
+	if err := docker.IsRunning(); err != nil {
+		return err
+	}
 	return c.forEachMachine(c.DeleteMachine)
 }
 
 // Inspect will generate information about running or stopped machines.
 func (c *Cluster) Inspect(hostnames []string) ([]*Machine, error) {
+	if err := docker.IsRunning(); err != nil {
+		return nil, err
+	}
 	machines, err := c.gatherMachines()
 	if err != nil {
 		return nil, err
@@ -510,6 +519,9 @@ func (c *Cluster) startMachine(machine *Machine, i int) error {
 
 // Start starts the machines in cluster.
 func (c *Cluster) Start(machineNames []string) error {
+	if err := docker.IsRunning(); err != nil {
+		return err
+	}
 	if len(machineNames) < 1 {
 		return c.forEachMachine(c.startMachine)
 	}
@@ -545,6 +557,9 @@ func (c *Cluster) stopMachine(machine *Machine, i int) error {
 
 // Stop stops the machines in cluster.
 func (c *Cluster) Stop(machineNames []string) error {
+	if err := docker.IsRunning(); err != nil {
+		return err
+	}
 	if len(machineNames) < 1 {
 		return c.forEachMachine(c.stopMachine)
 	}

pkg/docker/pull.go

@@ -62,6 +62,16 @@ func Pull(image string, retries int) error {
 	return err
 }
 
+// IsRunning checks if Docker is running properly
+func IsRunning() error {
+	cmd := exec.Command("docker", "info")
+	if err := cmd.Run(); err != nil {
+		log.WithError(err).Infoln("Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?")
+		return err
+	}
+	return nil
+}
+
 func setPullCmd(image string) exec.Cmd {
 	cmd := exec.Command("docker", "pull", image)
 	cmd.SetStderr(os.Stderr)