An unexpected alarm is triggered when vCenter Server is rebooted

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:
While rebooting vCenter Server, an unexpected alarm is triggered.

Environment

VMware vCenter Server 5.5.x
VMware vCenter Server 6.5.x
VMware vCenter Server 5.1.x
VMware vCenter Server 6.0.x
VMware vCenter Server 5.0.x
VMware vCenter Server 6.7.x

Resolution

There is no workaround at the moment. After vCenter Server reboot some alarms are triggered unexpectedly. This is because of the unexpected input send to alarms due to the transitional state of vCenter Server (being rebooted). Usually an alarm triggered by an event will reset to a normal state automatically if vCenter Server retrieve the event that identifies the normal condition after rebooting vCenter Server. However some alarms could not reset to the normal state if vCenter Server does not retrieve the normal condition, the alarm still remains. In such cases, reset the alarm manually in the vSphere Web Client to return it to a normal state. 
To reset the alarm in vCenter Server:

1. Log in to the vSphere Web Client using an account with administrator privileges.
2. Select the affected inventory object.
3. Select Monitor > Alarms.
4. Select the alarm.
5. Click Reset to Green

If you do not observe any actual problem which related the alarm after rebooting vCenter Server, you can safely ignore the alarm.