Observability & Alerting 5 min read

Prometheus Alertmanager Tutorial

Configure Prometheus Alertmanager for alert routing, Slack webhook notifications, inhibition rules, and high availability (HA) deduplication.

1. Alertmanager Architecture Overview

Prometheus handles metric evaluation and fires alerts based on PromQL rules. Alertmanager acts as the central notification router: handling deduplication, grouping, inhibition, and dispatch to Slack, PagerDuty, or Opsgenie.

2. Configuring Alert Routing (`alertmanager.yml`)

Below is a battle-tested Alertmanager YAML configuration file provided in VibeInfra's monitoring stack:

yaml

global:
  resolve_timeout: 5m
  slack_api_url: 'https://hooks.slack.com/services/T00/B00/X00'

route:
  group_by: ['alertname', 'cluster', 'service']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 12h
  receiver: 'slack-notifications'

receivers:
- name: 'slack-notifications'
  slack_configs:
  - channel: '#alerts-production'
    send_resolved: true
    title: '[{{ .Status | toUpper }}] {{ .CommonLabels.alertname }}'
    text: '{{ range .Alerts }}{{ .Annotations.summary }}\n{{ end }}'

3. High Availability (HA) & Deduplication

To prevent duplicate notifications when running multiple Alertmanager instances, connect them via gossip mesh networking.

⚡ HA Tip: Deploy Alertmanager using VibeInfra Helm charts with alertmanager.cluster.peers enabled so redundant alerts are automatically suppressed.