What is a namespace?

A namespace in Kubernetes is a mechanism for virtual grouping of objects (pods, services, deployments, etc.) within a single cluster. It provides logical separation of resources, isolation, access control, and prevents name conflicts.

Main properties:

• Isolation: Objects in one namespace are not directly visible in another.
• Access control: RBAC policies can be applied to namespaces, restricting user or group access to resources within a specific namespace.
• Scalability: Allows organizing a cluster with many teams or applications without overlaps.
• Conflict prevention: Objects in different namespaces can have the same names.

Examples of usage:

• Separation of environments (development, staging, production).
• Division by teams or projects.
• Resource management for different applications.

Each Kubernetes cluster has predefined namespaces:

• default: The default namespace for objects not explicitly specified.
• kube-system: For system objects created by Kubernetes.
• kube-public: For resources visible to all users.
• kube-node-lease: Contains Lease objects for tracking node availability.

# Example of creating a namespace
apiVersion: v1
kind: Namespace
metadata:
  name: my-app

# Switching context to a namespace
kubectl config set-context --current --namespace=my-app

# Viewing objects in a specific namespace
kubectl get pods -n my-app

# Viewing all namespaces
kubectl get namespaces