Kubernetes Namespaces: Organize Your Cluster

Namespaces provide a way to divide cluster resources between multiple users, teams, or environments.

Default Namespaces

Creating Namespaces

# Imperative
kubectl create namespace development

# YAML
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Namespace
metadata:
  name: production
EOF

Working with Namespaces

# List namespaces
kubectl get namespaces

# Get resources in specific namespace
kubectl get pods -n development

# Get resources in all namespaces
kubectl get pods -A

# Set default namespace for context
kubectl config set-context --current --namespace=development

Resource Quotas

Limit total resources per namespace:

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-quota
  namespace: development
spec:
  hard:
    requests.cpu: "4"
    requests.memory: 8Gi
    limits.cpu: "8"
    limits.memory: 16Gi
    pods: "20"
    services: "10"

Limit Ranges

Set default and max limits for containers:

apiVersion: v1
kind: LimitRange
metadata:
  name: default-limits
  namespace: development
spec:
  limits:
  - default:
      cpu: 500m
      memory: 256Mi
    defaultRequest:
      cpu: 100m
      memory: 128Mi
    max:
      cpu: "2"
      memory: 1Gi
    type: Container

Cross-Namespace Communication

Services can be accessed across namespaces:

# Full DNS name
curl http://service-name.namespace.svc.cluster.local

# Example
curl http://database.production.svc.cluster.local:5432

Best Practices

1. Separate environments: dev, staging, production
2. Team-based isolation: frontend, backend, data
3. Apply resource quotas: Prevent resource hogging
4. Use RBAC per namespace: Control access
5. Consistent naming: Use clear, descriptive names

Common Exam Tasks

• Create namespace
• Deploy resources to specific namespace
• Configure ResourceQuota
• Access service across namespaces

Practice Namespaces

Namespace management appears in CKA exams. Practice at Sailor.sh.

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