ALERT K8SSchedulerDown
  IF absent(up{job="kube-scheduler"}) or (count by(cluster) (up{job="kube-scheduler"} == 1) == 0)
  FOR 5m
  LABELS {
    severity = "critical",
  }
  ANNOTATIONS {
    summary = "Scheduler is down",
    description = "There is no running K8S scheduler. New pods are not being assigned to nodes.",
  }