To clear an alarm in vSphere Client for a host that has failed, which steps should an administrator take?

To clear an alarm in vSphere Client for a host that has failed, the step that is most appropriate is to access the triggered alarms and select the option to reset the alarm to green. This action indicates to the system that the underlying issue has been remedied or is no longer relevant, thereby updating the alarm status to reflect that there is no longer a problem.

The 'Reset to Green' option is specifically designed for scenarios where an alarm alert has been addressed. It reassures the management system that the issue flagged by the alarm has been effectively resolved, which is a crucial procedure in maintaining proper monitoring and management of virtual infrastructure. This helps ensure that notifications correspond accurately with the current state of the host, thereby reducing unnecessary alerts.

Following this method is particularly important for maintaining an accurate state of the system and helps in preventing administrators from being overwhelmed with irrelevant alarm triggers after the issues have been addressed. This maintains operational efficiency and clarity in monitoring data center environments.