when Alertmanager sends again after group_interval elapsed, it will notify about both alerts or just the newest alerts?

[zhang windy]

Hi Team, I have a problem, please clarify,  thank you .

 In this situation:

As an example: A single alert rule (in prometheus) fires with a label set {foo="bar", instance="instanceA"}. Alertmanager sends an alert and is added to a new alert group. Then, the same alert rule fires again with a different label set {foo="bar", instance="instanceB"}. This is also added to the same alert group. Alertmanager won't send an additional alert out until after the time in group_interval.

when Alertmanager sends again after group_interval elapsed, it will notify about both alerts or about {foo="bar", instance="instanceB"} only? I feel confuesd, thank you very much.

[Brian Candler]

It will send a single message containing details of *all* the active alerts in the group.