How much time an alert takes to fire

[debbiswal]

Hi ,
I have an alert rule configured in Prometheus is like this :
- alert: K8SSchedulerDown
expr: absent(up{job="kube-scheduler"} == 1)
for: 5m
labels:
severity: critical

And the AlertManager is configured with default 'repeat_interval' to 3 minutes.

I have 2 questions :

1. How much time it will take for the above alert to move to PENDING state , and How much time it will take to move to FIRING state. Is 5(Inactive to Pending )+5 (Pending to Firing) minutes , it takes to FIRING.
2. If the alert will be moved to FIRING state after 5 or 10 minutes , then why I am getting alerts in 3 minutes(is it due to the repeat_interval settings)

[simonpasquier]

The alert will be in firing state after 5 minutes (+ up to the evaluation interval of the rules group).
Then AlertManager will notify the alert after group_wait of the matching route.

I'm closing it for now. If you have further questions, please use our user mailing list, which you can also search.

[juliusv]

This post might also be interesting: https://pracucci.com/prometheus-understanding-the-delays-on-alerting.html

[debbiswal]

Yes @juliusv , Already I went through that . But if u see the diagram , as per Marco , 1 minute for switch from inactive to pending . And 1 more minute for switching from pending to firing state. So , does it take 2 minutes to fire?

[juliusv]

@debbiswal With a 1m eval duration and 1m for duration, that is the maximum time it should take, yes. Please take further usage questions to the mailing list and/or IRC channel though...

[debbiswal]

Thanks @juliusv .

[lock]

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