What are resource requests and limits in Kubernetes, and why are they important?

Requests tell the Kubernetes scheduler how much CPU/memory to reserve for a pod when scheduling it onto a node. Limits are the hard caps — the container is throttled (CPU) or killed (memory) if it exceeds them.

resources:
  requests:
    memory: "128Mi"
    cpu: "250m"
  limits:
    memory: "256Mi"
    cpu: "500m"

Always set both. Without requests, the scheduler cannot make good placement decisions. Without limits, a runaway container can starve other workloads on the same node (the “noisy neighbor” problem).