Sample Alert For Expiring Cert Manager Certificates

cert-manager-cert-alert.yml

apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: ingress-certificate-expiry
  namespace: monitoring
  labels:
    prometheus: k8s
    role: alert-rules
spec:
  groups:
  - name: IngressCertificateExpiry
    rules:
    - alert: CertificateMissedExpectedRotation28Days
      annotations:
        message: Certificate for {{ $labels.instance }} will expire in less than 28 days, has not been rotated as expected.
      expr: |-
        (probe_ssl_earliest_cert_expiry - time()) < ( 86400 * 28 )
      for: 15m
      labels:
        severity: warning
    - alert: CertificateMissedExpectedRotation24Hours
      annotations:
        message: Certificate for {{ $labels.instance }} will expire in less than 24 hours, has not been rotated as expected.
      expr: |-
        (probe_ssl_earliest_cert_expiry - time()) > ( 3600 * 24 )
      for: 15m
      labels:
        severity: critical