Limit ranges for defaults in Kubernetes - Mini Project: Build & Apply

Limit Ranges for Defaults in Kubernetes

📖 Scenario: You are managing a Kubernetes cluster where developers deploy their applications. To ensure fair resource usage and avoid accidental overconsumption, you want to set default resource limits and requests for all pods in a namespace.

🎯 Goal: Create a Kubernetes LimitRange resource that sets default CPU and memory requests and limits for containers in a namespace.

📋 What You'll Learn

Create a LimitRange YAML manifest named limitrange.yaml

Set default CPU request to 100m and default memory request to 200Mi

Set default CPU limit to 500m and default memory limit to 500Mi

Apply the LimitRange to the development namespace

💡 Why This Matters

🌍 Real World

In real Kubernetes clusters, setting default resource limits helps avoid resource starvation and ensures fair sharing among applications.

💼 Career

DevOps engineers and cluster administrators use LimitRanges to enforce resource policies and maintain cluster stability.

1

Create the basic LimitRange YAML skeleton

Create a YAML file named limitrange.yaml with the following top-level keys: apiVersion set to v1, kind set to LimitRange, and metadata with name set to resource-limits and namespace set to development.

Kubernetes

apiVersion: v1
kind: LimitRange
metadata:
  name: resource-limits
  namespace: development
# Your code here

Need a hint?

Use the apiVersion, kind, and metadata fields to define the LimitRange resource.

2

Add the spec and limits section

Add a spec section with a limits list containing one item. This item should have type set to Container.

Kubernetes

apiVersion: v1
kind: LimitRange
metadata:
  name: resource-limits
  namespace: development
spec:
  limits:
  - type: Container
  # Your code here

Need a hint?

The spec section defines the rules. The limits list holds the limit definitions.

3

Set default CPU and memory requests and limits

Inside the limits item, add defaultRequest with cpu: 100m and memory: 200Mi, and default with cpu: 500m and memory: 500Mi.

Kubernetes

apiVersion: v1
kind: LimitRange
metadata:
  name: resource-limits
  namespace: development
spec:
  limits:
  - type: Container
    # Your code here

Need a hint?

Use defaultRequest for default resource requests and default for default limits.

4

Apply the LimitRange to the development namespace and verify

Run the command kubectl apply -f limitrange.yaml to create the LimitRange in the development namespace. Then run kubectl get limitrange resource-limits -n development -o yaml to display the applied LimitRange.

Kubernetes

apiVersion: v1
kind: LimitRange
metadata:
  name: resource-limits
  namespace: development
spec:
  limits:
  - type: Container
    defaultRequest:
      cpu: 100m
      memory: 200Mi
    default:
      cpu: 500m
      memory: 500Mi
# Your code here

Need a hint?

Use kubectl apply -f limitrange.yaml to apply and kubectl get limitrange resource-limits -n development -o yaml to verify.