Documentation Plugins Prometheus Alerting Monitor alerts Alerts page

Alerts page

The Alerts page shows what the selected Alertmanager currently holds. It’s the Alertmanager’s view, so it shows alerts that have finished their pending period and been sent. Pending alerts don’t appear here.

Alert states

Alerts are counted in three states, each available as a filter:

A large suppressed count is worth a look. It usually means an over-broad silence or an inhibition rule doing more than intended, and both hide real problems.

Reading the list

The Receiver column is the one that answers “where did this go?” It reflects the route that actually matched, not the route you think should have matched.

Filter alerts

• Filter by labels accepts matchers such as foo=bar and env=~prod.*, so you can narrow by regex as well as exact value.
• Filter by receiver narrows to alerts routed to a particular receiver.
• The Active, Suppressed, and Unprocessed filters narrow by state.

Alert details

Select an alert to open a drawer with:

• Labels and Annotations: the alert’s identity, and what it says about itself.
• Timing: when it started, when it ends, and when it was last updated.
• Receivers: where it was routed.
• Generator URL: a link back to the rule in the source system.

If the alert is suppressed, the drawer names the cause: which silence silenced it, which inhibition rule inhibited it, or which time interval muted it. This is the fastest way to answer why a firing alert didn’t page anyone.

An empty page

If no alerts are listed, the plugin says none were found in the Alertmanager. That’s expected when nothing is wrong, but it’s also what a misconfiguration looks like.

To tell them apart, check the Rules page. Rules firing there but no alerts here means the ruler is sending to a different Alertmanager than the one selected. Refer to Troubleshooting.