martinbrook/kube-schedule-scaler

Kubernetes Controller which provides schedule scaling to Kubernetes deployments

Kubernetes Schedule Scaler

This Application/ Kubernetes controller is used to schedule scale Horizontal Pod Autoscaler. If hpa is configured the controller can adjust minReplicas and maxReplicas. At the moment it supports reading the scaling definitions from:

• directly in the annotations

Usage

Just add the annotation to your Horizontal Pod Autoscaler.

  annotations:
    kube-schedule-scaler/schedule-actions: '[{"schedule": "10 18 * * *", "replicas": "3"}]'

Available Fields

The following fields are available

• schedule - Typical crontab format
• replicas - the number of replicas to scale to
• minReplicas - in combination with an hpa will adjust the minReplicas else be ignored
• maxReplicas - in combination with an hpa will adjust the maxReplicas else be ignored

HorizontalPodAutoscaler Example

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  annotations:
    kube-schedule-scaler/schedule-actions: '[{"schedule": "53 18 * * *", "minReplicas": "3"}]'
  labels:
    app: hello-kubernetes
  name: hello-kubernetes
spec:
  maxReplicas: 10
  minReplicas: 1
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: hello-kubernetes
  targetCPUUtilizationPercentage: 70
status:
  currentCPUUtilizationPercentage: 0
  currentReplicas: 2
  desiredReplicas: 2

Debugging

If your scaling action has not been executed for some reason, you can check with the below steps:

kubectl get pod | grep kube-schedule
kube-schedule-scaler-75644b8f79-h59s2                    1/1       Running                 0          3d

Check for specific deployment at specific time

kubectl logs kube-schedule-scaler-87f9649f5-btnt7 | grep nginx-deployment-2 | grep "28-12-2018 09:50"
Deployment nginx-deployment-2 has been scaled successfully to 4 replica at 28-12-2018 09:50 UTC

You can also check from scalyr side

$application == "kube-schedule-scaler" 'nginx-deployment-2'