Trigger Specification

This specification describes the cron trigger that scales workloads in/out based on a cron Schedule.

triggers:
- type: cron
  metadata:
    # Required
    timezone: Asia/Kolkata  # The acceptable values would be a value from the IANA Time Zone Database.
    start: 30 * * * *       # Every hour on the 30th minute
    end: 45 * * * *         # Every hour on the 45th minute
    desiredReplicas: "10"

Parameter list:

• timezone - One of the acceptable values from the IANA Time Zone Database. The list of timezones can be found in: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones.
• start - Cron expression indicating the start of the cron schedule.
• end - Cron expression indicating the end of the cron schedule.
• desiredReplicas - Number of replicas to which the resource has to be scaled between the start and end of the cron schedule.

Notice: Start and end should not be same.

For example, the following schedule is not valid:

start: 30 * * * *
end: 30 * * * *

How does it work?

The CRON scaler allows you to define a time range in which you want to scale your workloads out/in.

When the time window starts, it will scale from the minimum number of replicas to the desired number of replicas based on your configuration.

What the CRON scaler does not do, is scale your workloads based on a recurring schedule.

Example

apiVersion: keda.k8s.io/v1alpha1
kind: ScaledObject
metadata:
  name: cron-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    deploymentName: my-deployment
  triggers:
  - type: cron
    metadata:
      timezone: Asia/Kolkata
      start: 30 * * * *
      end: 45 * * * *
      desiredReplicas: "10"