Using Horizontal Pod Autoscaling along with resource requests and limits
No, HPA is not looking at limits at all. You can specify target utilization to any value even higher than 100%.
Hi in deployment we have resources requests and limits. As per documentation here those parameters acts before HPA gets main role as autoscaler:
- When you create a Pod, the Kubernetes scheduler selects a node for the Pod to run on. Each node has a maximum capacity for each of the resource types: the amount of CPU and memory it can provide for Pods.
- Then the kubelet starts a Container of a Pod, it passes the CPU and memory limits to the container runtime.
- If a Container exceeds its memory limit, it might be terminated. If it is restartable, the kubelet will restart it, as with any other type of runtime failure.
If a Container exceeds its memory request, it is likely that its Pod will be evicted whenever the node runs out of memory.
On the other hand:
The Horizontal Pod Autoscaler is implemented as a control loop, with a period controlled by the controller manager’s (with default value of 15 seconds). The controller manager queries the resource utilization against the metrics specified in each HorizontalPodAutoscaler definition.
Note:Please note that if some of the pod’s containers do not have the relevant resource request set, CPU utilization for the pod will not be defined and the autoscaler will not take any action for that metric.
Hope this help