Why You Need an HPA for Every Container
HPA = Horizontal Pod Autoscaler. POD
You need to configure resource request values for all of your containers in Kubernetes because HPA makes scaling decisions based on those values. It makes those on the POD layer. So, you say "we need to scale the number of pods based on these resources utilization targets" in the HPA. The containers inside the pods will be sized according to their specific needs.
(I'm still learning how you can scale the size/number of the nodes.)
HPA is a controller that automatically adjusts the number of pods in an application based on metrics like CPU or memory usage. This dynamic scaling helps ensure that applications can handle varying loads efficiently. It uses metrics from the metrics server to compare the current resource usage to the HPA definition to decide if scaling is needed.
HPA makes scaling decisions based on resource request values at the container level. Therefore, it is essential to have configured the resource request values for all of your containers, individually.