Kubernetes Resource Limits: No CPU Limits, Memory Limit = Request

The Rule (Tim Hockin, K8s maintainer at Google)

• Memory: limits = requests (always)
• CPU: Never set CPU limits

The Config

# Correct
resources:
  requests:
    cpu: 500m
    memory: 256Mi
  limits:
    memory: 256Mi  # equals request, no CPU limit

# Wrong - causes unnecessary CPU throttling
resources:
  requests:
    cpu: 500m
    memory: 256Mi
  limits:
    cpu: 1000m     # remove this
    memory: 512Mi  # should equal request

Why

• CPU limits cause CFS throttling even when the node has spare CPU. Your pod gets slower for no reason.
• Memory limit > request = node overcommit. The kernel OOM killer starts randomly evicting pods under pressure.

Check for existing LimitRanges that might override

kubectl get limitrange -A

Gotcha

• VPA (Vertical Pod Autoscaler) sets CPU limits by default in some versions — check the updatePolicy
• If a namespace has a LimitRange with defaultLimit for CPU, every pod without explicit limits gets one forced on it
• GKE Autopilot ignores your settings and enforces its own limits