metrics-sample-rest/manifest/monitoring/alert-rule.yml

apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: hello-response-time-alerts
  namespace: metrics
spec:
  groups:
    - name: max-response-times
      interval: 30s
      rules:
        - alert: max-response-time-too-long
          expr: avg(hello_seconds{quantile="1.0"}) > 0.2
          for: 1m