groups:
- name: alert.rules
  rules:
  - alert: InstanceDown
    expr: up{job="node-exporter"} == 0
    for: 5m
    labels:
      severity: critical
    annotations:
      summary: "Endpoint {{ $labels.instance }} down"
      description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 5 minutes."