This article applies to FOG 1.3.0.
When evaluating how GreenFOG was being used, we came to the conclusion that there was room for significant improvements to the entire module. We believe this new module will achieve what we always wanted from GreenFOG: scheduled power management of your entire network. This module lets you define for each host, or group, a CRON schedule for power operations and the ability to execute power operations on demand. Note: Your hosts must be set to allow WOL packets inorder for the startup tasks to work
Wake On Lan, Shutdown, and Reboot tasks can be scheduled using CRON. In the below screenshot, a host is set to shutdown every Friday at 00:00, and turn on every Monday at 06:30. If you are new to CRON, there are many sites to help you create schedules, such as CronTab.Guru which will show you what a CRON expression means in english.
On Demand Tasks
Wake On Lan, Shutdown, and Reboot tasks can be set to run immediately. In the below screenshot, by clicking the Add button, the host will immediately Shutdown as soon as it contacts the FOG server, which depends on your checkin time configuration. On Demand tasks can be applied to a single host, or an entire group.
How it interacts with logged on users
If a person is using a computer when a shutdown or reboot task is set to run, they will be prompted by a dialog. They can choose to abort the operation if they are not yet finished working. After aborting, that power task is ignored and will not prompt them again.
If you would like to ensure that all computers are shutdown / restarted you can create multiple CRON tasks. For example, you could schedule a shutdown every day at 20:00 and again at 22:00. This way if a user aborts the 20:00 shutdown, the client will retry at 22:00.
CRON tutorials online
While reading the below links, keep in mind that the only part of these articles that apply to FOG is the scheduling syntax, not the file paths.