A HorizontalPodAutoscaler (HPA) is a Kubernetes controller that automatically changes the number of pod replicas to match observed demand. It usually watches metrics such as CPU, memory, or custom application signals, then adds or removes pods to keep a service within target thresholds. This makes it a core part of elastic cloud infrastructure.
In security operations, HPA matters because scaling decisions depend on trusted telemetry. If metrics are misconfigured, spoofed, or noisy, a workload may scale too slowly, waste resources, or create an outage. Attackers can try to trigger excessive scaling with traffic spikes or by influencing the metric source, causing denial of service or cost abuse. Defenses include secure metrics pipelines, strong RBAC, sane limits, and testing autoscaling behavior under load.