Resource Requests and Limits¶

Description¶

Kubernetes allows you to define resource requests and limits for containers to control how much CPU and memory they can use.

Resource management ensures that workloads receive the resources they need while preventing individual containers from consuming excessive cluster resources.

These settings are defined in the container specification of a Pod or Deployment.

Resource Requests¶

A request defines the minimum amount of CPU or memory guaranteed for a container.

The Kubernetes scheduler uses requests to determine which node can run the pod.

Example:

resources:
  requests:
    cpu: "250m"
    memory: "128Mi"

This ensures the container is scheduled on a node with at least the specified resources available.

Resource Limits¶

A limit defines the maximum amount of resources a container can consume.

If a container exceeds its defined limit:

CPU usage is throttled
Memory usage may cause the container to be terminated

Example:

resources:
  limits:
    cpu: "500m"
    memory: "256Mi"

Example Pod Configuration

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
    resources:
      requests:
        cpu: "250m"
        memory: "128Mi"
      limits:
        cpu: "500m"
        memory: "256Mi"

Units | Resource | Unit Example | Description | |----------|--------------|-------------| | CPU | 500m | 500 millicpu (0.5 CPU core) | | Memory | 128Mi | 128 mebibytes |

View Resource Usage¶

You can inspect resource usage using:

kubectl top pods

View node resource usage:

kubectl top nodes

Best Practices¶

Always define resource requests and limits
Avoid extremely high limits that could destabilize nodes
Monitor resource usage using metrics tools
Test workloads under expected load

Horizontal Pod Autoscaler
Pod scheduling