Horizontal Pod Autoscaler Operations

Internal

• Horizontal Pod Autoscaler
• Kubernetes Operations

Create an Autoscaler

CPU-Based Autoscaler

For the autoscaler to work, the pods subject to autoscaling must have their CPU requests set.

With CLI

https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#autoscale

kubectl autoscale deployment <deployment-name> --cpu-percent=50 --min=1 --max=10

With Metadata

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: example
spec:
  minReplicas: 1
  maxReplicas: 5
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: httpd
  metrics:
    - type: Resource
      resource:
        name: cpu
        target:
          type: Utilization
          averageUtilization: 50

Playground

https://github.com/ovidiuf/playground/tree/master/kubernetes/horizontal-pod-autoscaler/cpu-based

Horizontal Pod Autoscaler Controller Configuration

--horizontal-pod-autoscaler-sync-period

Sets the period of the control loop. By default, the value is 15 seconds.

--horizontal-pod-autoscaler-tolerance

See:

Autoscaling Algorithm

--horizontal-pod-autoscaler-downscale-stabilization

The value for this option is a duration that specifies how long the autoscaler has to wait before another downscale operation can be performed after the current one has completed. The default value is 5 minutes. Also see:

Autoscaling Algorithm

--horizontal-pod-autoscaler-use-rest-clients

This should be set to true or be unset to configure the autoscaler to read metrics from metrics APIs. Setting this to false switches to Heapster-based autoscaling, which is deprecated. Also see:

How Horizontal Pod Autoscaler Works

Horizontal Pod Autoscaler Controller Troubleshooting

Horizontal Pod Autoscaler operations are logged in the controller-manager logs. Failures such as not being able to pull a specific metric from a certain metrics API are logged there.