Interactive Explainer

🎯Key Takeaways

Namespaces provide logical isolation and enable multi-tenancy; use them even in single-team clusters

Labels are flexible metadata for organization; Service selectors match labels dynamically

Namespace isolation combined with RBAC, NetworkPolicies, and quotas enable secure multi-tenancy

Default namespace should never be used for application workloads; enforce namespace requirements

Namespaces & Labels: Multi-Tenancy, Organization, and Resource Selection

Namespaces partition a cluster into isolated logical units. Labels are metadata selectors that enable flexible resource organization and querying.

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What you'll learn

Namespaces provide logical isolation and enable multi-tenancy; use them even in single-team clusters
Labels are flexible metadata for organization; Service selectors match labels dynamically
Namespace isolation combined with RBAC, NetworkPolicies, and quotas enable secure multi-tenancy
Default namespace should never be used for application workloads; enforce namespace requirements

Lesson outline

Namespaces: Logical Isolation

Namespace is a cluster partition. Most Kubernetes resources live in a namespace (Pods, Services, Deployments, etc.). Some are cluster-wide (Nodes, PersistentVolumes, ClusterRoles).

Default namespaces: default (user workloads), kube-system (K8s internals), kube-public (public data), kube-node-lease (node heartbeats).

Resource quotas and network policies can be applied per-namespace for multi-tenancy.

Labels and Selectors

Label: key-value pair attached to Kubernetes objects. E.g., app=myapp, tier=backend, env=prod.

Selector: query that matches labels. E.g., app=myapp,env=prod matches objects with both labels. Used by Services, Deployments, and queries.

Labels are arbitrary and used for organization, not by Kubernetes automatically (except node labels for scheduling).

Label Best Practices

Common labels (recommended by Kubernetes): app, instance, version, component, part-of, managed-by, created-by.

Example: app=myapp, app.kubernetes.io/name=myapp, app.kubernetes.io/version=v1.2.3, app.kubernetes.io/managed-by=helm.

Namespacing Strategies

By environment: dev, staging, prod. Each team has dedicated namespace(s). Isolation via RBAC and NetworkPolicies.

By team: each team owns a namespace. Limits resource allocation per team. Enables self-service deployments.

By application: one namespace per application, multiple environments (using labels). Reduces namespace count.

Key takeaways

Namespaces provide logical isolation and enable multi-tenancy; use them even in single-team clusters
Labels are flexible metadata for organization; Service selectors match labels dynamically
Namespace isolation combined with RBAC, NetworkPolicies, and quotas enable secure multi-tenancy
Default namespace should never be used for application workloads; enforce namespace requirements

🧠Mental Model

💡 Analogy

Namespaces are like separate buildings in a city. Labels are like tags on buildings (color, purpose, size). A Service selector is like looking for "red buildings with "cafe" tag". Namespaces provide hard isolation; labels provide flexible organization within and across namespaces.

⚡ Core Idea

Namespaces provide logical partition and RBAC/quota boundaries. Labels are metadata for flexible organization and selection.

🎯 Why It Matters

In multi-tenant clusters, namespaces isolate teams and limit blast radius. Labels enable flexible resource organization without physical partitioning.

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