[FEATURE REQUEST] Alertmanager receiver for Suppressed Alerts

Problem Statement

Currently, Alertmanager does not expose metrics for silenced alerts, making it difficult to track them without manually navigating to the Alertmanager UI. Also, polling the /silences endpoint to know what alerts are silenced is inconvenient. The issue is better solved upstream on alertmanager side.

Proposed Solution

Add an optional suppressed receiver for an alert matcher: For an alert that matches an alertmanager route and has some sort of suppress configured, Alertmanager will hit the suppressed receiver instead when alert.state is suppressed. Otherwise, no-ops. This implementation is simple as there are existing egress mechanisms doing this for firing state.

Example Scenario

During a planned maintenance window, an alert is silenced. The new egress mechanism will notify a new receiver responsible for handling silences. This is very useful for critical services undergoing maintenance and require silencing to take further actions.

Benefits

• Automated Notifications
• Improved Visibility
• Efficient Monitoring
• Allows Auditing

Start by reviewing Alertmanager’s existing egress mechanisms and the /silences endpoint described in the issue. Trace how a route matcher handles firing alerts and how alert.state represents suppressed; the feature is done when an optional suppressed receiver can handle matching silenced alerts without changing the normal path.