Comment 1 for bug 1971156

A simple reproducer is deploying NRPE as shown from the charm help, and then running the check with no arguments:

juju deploy ubuntu
juju deploy nrpe
juju deploy nagios
juju add-relation ubuntu nrpe
juju add-relation nrpe:monitors nagios:monitors
juju wait
juju run-action --wait nrpe/0 run-nrpe-check name=check-reboot

Currently SQA has a nagios validator which
1) lists all the checks for a NRPE unit
2) runs the nrpe check for each check
3) reports the errors.

Check reboot comes up as an listed check, but when ran with no argument reports as a failed check. I feel like the check should be able to check the juju kv for the known reboot time, if there is no known reboot time, it does nothing, otherwise does the compare.
ack-reboot can then behave the way it does currently.