Unexpected Reboot on Dell ThinOS When Power Sleep Policy and Scheduled Reboot are Both Implemented

Affected Operating Systems:

• Dell ThinOS 9.X

• Devices reboot unexpectedly during working hours.
• Scheduled reboots are not honored at the specified time.
• Devices may reboot after waking up from sleep mode, even if the scheduled reboot time has passed.

This issue occurs when both the Power Sleep Policy and Scheduled Reboot Policy are configured on the devices. When both policies are active, the device may enter sleep mode while a scheduled reboot is pending, leading to an unexpected reboot.

This is happening because the scheduler is using a countdown value rather than setting a specific date/time for the reboot. The countdown is suspended during sleep and resumes upon waking up. The scheduled reboot is not cancelled if the scheduled time for the reboot has passed, causing the device to reboot at an unwanted time.

Checking the wlogd.log logs of an affected device, it should be possible to see something similar to the logs below:

• The reboot policy of the device is set:

  [2024-10-10 15:41:22.333] T/WebUIProc/WebUIModule (0/0) Schedule 'reboot' TimeRange: 00:01-06:00, wdays: Sunday,Tuesday,Monday,Wednesday,Thursday,Friday,Saturday, delayWeek: 0

• At 15:41, the reboot is scheduled for 2:36 AM, which is 10 hours and 55 minutes later.

  [2024-10-10 15:41:23.188] N/WebUIProc/WebUIModule (0/0) Reboot is scheduled at 02:36 on 2024-10-11 (Fri.).

• The device goes to sleep at 21:02, which is 5 hours and 21 minutes after 15:41, leaving 5 hours and 34 minutes before the scheduled reboot.

  [2024-10-10 21:02:01.345] N/system_daemon  /system          (537/35512) Device Going To Sleep...

• At 02:36, the device is still sleeping, so the reboot does not occur.
• At 06:58, the device wakes up.

  [2024-10-11 06:58:32.543] V/audiomanager_da/audioManager    (1837/34945) hotplug_process 1225---->action:PLUGOUT

• At 12:32, the device reboots itself, which is 5 hours and 34 minutes after waking up.

  [2024-10-11 12:32:20.788] N/system_daemon  /system          (537/36058) Rebooting...  

To resolve this issue, follow these steps to disable either the Power Sleep Policy or the Scheduled Reboot Policy.

To disable the Power Sleep policy:

1. Go in the console to Groups & Configs > Edit Policies > ThinOS 9.x
2. On the left pane, select Advanced > System Settings > Power Sleep Settings and switch the Sleep mode to Off
   
3. To apply the policy, click Save & Publish

To disable the Scheduled Reboot Policy:

1. Go in the console to Groups & Configs > Edit Policies > ThinOS 9.x
2. On the left pane, select Advanced > System Settings > Scheduled Reboot Settings and switch the Enable Auto Reboot off
   
3. To apply the policy, click Save & Publish

More details on how to edit the policy in Wyse Management Suite (WMS) are available here (reference the Edit the ThinOS 9.x policy settings):
Dell Wyse Management Suite Version 4.1.x Administrator Guide

More details on how to edit the policy in the Admin Policy Tool are available here (reference the Configure the Admin Policy Tool section):
Dell Wyse ThinOS Version 9.0 Operating System Release Notes