Definition. The classic Kubernetes component that scales predefined node groups (e.g. AWS Auto Scaling Groups, Azure Scale Sets) up and down according to pod demand. It acts at group level, not on individual instances, and works closely with pod scheduling and quotas.

Why it matters. For setups with stable node sizes and classic node pools, the Cluster Autoscaler remains the pragmatic default. With highly variable workloads, Karpenter often complements or replaces it.

Related. Karpenter, Kubernetes Worker Node, Platform Engineering