Overview
While HPA scales the number of Pods, the Vertical Pod Autoscaler (VPA) scales the size of the Pods. It ensures that Pods have the right amount of resources (CPU and RAM) to run efficiently without wasting cluster capacity.
Key Components
- Recommender: Monitors resource usage and provides recommendations for CPU and memory requests.
- Updater: Evicts Pods that need to be updated with new resource limits.
- Admission Controller: Intercepts Pod creation requests and applies the recommended resource limits.
Limitations
VPA currently requires restarting Pods to apply changes, which can cause brief downtime if not managed carefully. It is often used for applications that cannot be easily scaled horizontally.