configuring-hpa-based-on-application-metrics.adoc

Configuring HPA based on application metrics

If you configure an application to export metrics, you can set up Horizontal Pod Autoscaling (HPA) based on these metrics.

Procedure

1. Create a YAML file for your configuration. In this example, it is called deploy.yaml.

2. Add configuration for deploying the horizontal pod autoscaler for the application. This example configures and deploys HPA based on the application http_requests_per_second metric for the sample application configured in the "Application monitoring" section:

   apiVersion: autoscaling/v2beta1
   kind: HorizontalPodAutoscaler
   metadata:
     name: example-app-scaler
     namespace: default
   spec:
     scaleTargetRef:
       apiVersion: apps/v1
       kind: Deployment
       name: example-app (1)
     minReplicas: 3 (2)
     maxReplicas: 10 (3)
     metrics:
     - type: Pods
       pods:
         metricName: http_requests_per_second (4)
         targetAverageValue: 10 (5)

   1. name specifies the application.

   2. minReplicas specifies the minimum number of replicas for the HPA to maintain for the application.

   3. maxReplicas specifies the maximum number of replicas for the HPA to maintain for the application.

   4. metricName specifies the metric upon which HPA is based. Here, specify the metric you previously exposed for your application.

   5. targetAverageValue specifies the value of the metric for the HPA to try to maintain by increasing or decreasing the number of replicas.

3. Apply the configuration file to the cluster:

   $ oc apply -f deploy.yaml