Use swarm-cronjob to launch Gantry at a specific time.
In this example, we only want to run Gantry at the specific time, therefore we set replicas to 0 on the Gantry service to avoid running it as soon as the service is deployed. We also need to set restart_policy.condition to none to prevent Gantry from restarting automatically after a cronjob.
Refer to the swarm-cronjob document for more information.