Horizontal Scaling With Playgrounds

We only support HPA right now, but will try to integrate with KEDA and Knative in the future.

Install the Metric Server

HPA depends on the metric-server for scaling decisions, so we need to install it in prior, see install command below:

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

If probe failed, it may because of enabled TLS, set --kubelet-insecure-tls=true to disable the TLS verification.

## How to Use

If your backendRuntime has already configured the `scaleTrigger`, set the `playground.elasticConfig` like this:

```yaml
spec:
  elasticConfig:
    minReplicas: 1
    maxReplicas: 3

Or you can set the scaleTrigger directly in Playground like this:

spec:
  elasticConfig:
    minReplicas: 1
    maxReplicas: 3
    scaleTrigger:
      hpa:
        metrics:
          - type: Resource
            resource:
              name: cpu
              target:
                type: Utilization
                averageUtilization: 50