Scaling your pods with the horizontal pod autoscaler (HPA) based on standard metrics is not sufficient in may cases. That's where custom metrics help you to implement your best autoscaling behaviours. With the Kubernetes custom metrics API you add the metrics you need like queue length, concurrent requests or whatever and make it available to the HPA scaling policies. You will learn how to implement simple custom metrics, use it with the HPA, what custom metric extension exists and how you can benefit from it. Scale your cluster like you need it.