With https://issues.redhat.com/browse/OCPBUGS-15264 tzdata have been added to make sure the cron scaler is working and customer can apply their desired timezone. With https://docs.openshift.com/container-platform/4.15/nodes/cma/nodes-cma-rn/nodes-cma-autoscaling-custom-rn.html it seems that part is missing again and hence cron scalers are failing. While it's generally understood that cron scaler is not yet supported/maintained by Red Hat, it's considered a regression as tzdata used to be available in previous version and hence could be used.

Custom Metrics Autoscaler Operator 2.12.1-376

Always

1. Install OpenShift Container Platform 4.15 and Custom Metrics Autoscaler as per documentation (does not matter platform and install method)
2. Create a ScaledObject with a cron trigger with timezone applied

    apiVersion: keda.sh/v1alpha1
    kind: ScaledObject
    metadata:
      labels:
        scaledobject.keda.sh/name: cron-scaledobject
      name: cron-scaledobject
      namespace: project-2
    spec:
      scaleTargetRef:
        name: curl
      triggers:
      - metadata:
          desiredReplicas: "2"
          end: '*/10 * * * *'
          start: '*/5 * * * *'
          timezone: Europe/Zurich
        type: cron

3. Check keda-operator logs in openshift-keda namespace

ERROR   scale_handler   error getting scale decision    {"scaledObject.Namespace": "project-2", "scaledObject.Name": "cron-scaledobject", "scaler": "cronScaler", "error": "unable to load timezone. Error: unknown time zone Europe/Zurich"}

INFO	Reconciling ScaledObject	{"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "ScaledObject": {"name":"cron-scaledobject","namespace":"project-2"}, "namespace": "project-2", "name": "cron-scaledobject", "reconcileID": "6d3ae923-d3d1-4a16-9061-4601d07a2061"}

A request to have the cron scaler supported was raised via https://issues.redhat.com/browse/RFE-4173