Context

When using Prometheus Alertmanager to send alerts to incident.io, you might notice that some alerts don't appear as expected in the incident.io interface. This typically happens due to how Alertmanager groups alerts and how incident.io processes these grouped alerts.

Answer

The behavior you're seeing is related to how Prometheus Alertmanager groups alerts and how incident.io processes these grouped alerts. Here's what you need to know:

How Alertmanager Grouping Works

Alertmanager groups alerts based on the group_by labels specified in your route configuration. When multiple alerts share the same group labels, they're combined into a single notification. For example:

route: group_by: - job group_interval: 1m group_wait: 30s receiver: incident.io

How incident.io Processes Grouped Alerts

When incident.io receives grouped alerts from Alertmanager:

• Multiple alerts within the same group are treated as a single alert in incident.io

• Subsequent alerts with the same group key will be deduplicated while the original alert is still firing

• A new alert will only be created once the previous alert with the same group key has been resolved

Solutions

To ensure alerts appear as expected in incident.io, you can:

1. Adjust your group_by labels in the Alertmanager configuration to create more granular groupings

2. Wait for existing alerts to resolve before expecting new alerts with the same group key to appear

3. If you need individual alerts instead of grouped alerts, you can consider using the Grafana alert source instead of Alertmanager, as it handles grouped alerts differently.