code: func (c *ComputeUtil) configureInstance(d *Driver) error {
  	log.Infof("Configuring instance")
  
  	instance, err := c.instance()
  	if err != nil {
  		return err
  	}
  
  	if err := c.addFirewallTag(instance); err != nil {
  		return err
  	}
  
  	return c.uploadSSHKey(instance, d.GetSSHKeyPath())
  }
docs: // configureInstance configures an existing instance for use with Docker Machine.