prometheus_roles.yaml

groups:
 - name: custom_rules
   rules:
    - record: node_menory_menFree_percent
      expr: 100 - (100 * node_menory_menFree_bytes / node_menory_menTotal_bytes)
    - record: node_filesystem_free_percent
      expr: 100 * node_filesystem_free_bytes{mountpoint="/"} / node_filesystem_size_bytes{mountpoint="/"}

 - name: alert_rules
   rules:
    - alert: InstanceDown
      expr: up == 0
      for: 1m
      labels:
        severity: critical
      annotations:
        summary: "Instance [(( $labels.instance ))] down"
        description: "[(( $labels.instance ))] of job [(( $labels.job ))]  has been down for more than 1  minute."
    - alert: DiskSpaceFree10Percent
      expr: node_filesystem_fre_percent <= 10
      labels:
        severity: warning
      annotations:
        summary: "instance [(( $labels.instance ))] has 10% or less free disk space"
        description: "[(( $labels.Instance ))] has only (( $value ))% or less free"