Lab: Alerting with Prometheus and Alertmanager

What you will learn in this TP

• Write an alert rule
• Route to a receiver
• Use silences and amtool

End-to-end alerting #

What you will learn in this section

• Write an alert rule
• Route to a receiver
• Use silences and amtool

Context. An alert nobody receives protects nothing. You build the whole chain: Prometheus rule, Alertmanager routing, notification and a silence during maintenance.

Prerequisites : Docker Compose  ·  Estimated time : 40 min

From rule to notification.

1. 1. Deploy the stack

   Why? The three components must see each other: Prometheus evaluates, Alertmanager notifies, the exporter provides the target.

   Prometheus, Alertmanager and a node-exporter with Docker Compose.

2. 2. Write the alert rule

   Why? for avoids firing on a few seconds' blip: the alert goes through pending before firing.

   Fire InstanceDown when a target stops answering for 1 minute.

3. 3. Route to a receiver

   Why? A test webhook proves the notification really arrives, without depending on a chat tool.

   Send the alert to a test webhook (webhook.site or a small local server).

4. 4. Silence and validation

   Why? Silences let you work without noise; amtool validates the configuration before deploying.

   Create a 30-minute silence then validate the configuration with amtool.

Difficulty level : ●●●○○ (3/5)