Prometheus Alertmanager

An Alertmanager webhook receiver sends grouped Prometheus alerts to Squasher. Each alert in a group opens its own incident, and the same incident resolves when the alert resolves.

What you need

Access to alertmanager.yml and permission to reload Alertmanager.
The Squasher CLI, signed in with write access to the project. See Alert sources.

Connect Alertmanager

Create the connector

squasher alert-connectors create \
  --project "$SQUASHER_PROJECT_ID" \
  --provider prometheus_alertmanager \
  --display-name "Production Alertmanager"

Save setup.endpoint and setup.secret from the output.

Add a receiver

Add a receiver with the endpoint and the secret, and send alerts to it. Keep send_resolved: true, so that incidents resolve.

alertmanager.yml

route:
  receiver: squasher

receivers:
  - name: squasher
    webhook_configs:
      - url: "https://api.squasher.ai/v1/hooks/alert-connectors/<connector-id>"
        send_resolved: true
        http_config:
          authorization:
            type: Bearer
            credentials_file: /etc/alertmanager/squasher-secret

credentials_file keeps the secret out of the config. To send only some alerts, put the receiver on a child route with matchers.

Check and reload the config

amtool check-config alertmanager.yml
curl -X POST http://localhost:9093/-/reload

Test with a real alert

Let a Prometheus alert fire and resolve. Check that one incident opens in Incidents and that the same incident resolves.

How Squasher reads a notification

Alertmanager field	Squasher incident
`groupKey`	Required on each request. Not used for incidents.
`alerts[].fingerprint`	Alert key. Each alert keeps one incident until it resolves.
`alerts[].status: firing`	Opens the incident, or updates it if it is open.
`alerts[].status: resolved`	Resolves the incident.
`annotations.summary`	Title. Without it, Squasher uses `labels.alertname`.
`annotations.description`	Summary.
`labels.severity`	Severity. See Severity.
`startsAt`, `endsAt`	Event time for a firing and a resolved alert.
`labels`, `annotations`	Added to the message on the incident timeline.
`generatorURL`	Added to the message as a link, and the Open in Prometheus Alertmanager link of the incident. Without it, Squasher uses `externalURL`.

Squasher builds the event key from the fingerprint, the status, the time, the labels, and the annotations. Alertmanager repeats a firing alert at each repeat_interval; Squasher applies a repeat with the same content once.

Limits

Squasher sees only the alerts in the request. Leave max_alerts at 0 (no limit), so that Alertmanager does not drop alerts from a group.
An alert without a fingerprint, labels, or status is rejected. The other alerts are still applied, and Squasher returns 207.
Squasher reads at most 1,000 alerts from one request.

Get started

Guides

Prometheus Alertmanager

What you need

Connect Alertmanager

How Squasher reads a notification

Limits

Next steps

Alert sources

Route incidents

​What you need

​Connect Alertmanager

​How Squasher reads a notification

​Limits

​Next steps

Alert sources

Route incidents

What you need

Connect Alertmanager

How Squasher reads a notification

Limits

Next steps