How do you implement multi-tenancy and namespace isolation in Kubernetes?

Multi-tenancy in Kubernetes involves isolating resources and workloads between different teams, applications, or customers using namespaces and security controls.\n\nNamespace Isolation:\n• Logical cluster partitioning\n• Resource scoping and organization\n• RBAC boundary enforcement\n• Network policy isolation\n\nIsolation Levels:\n• Soft Multi-tenancy: Trusted tenants, shared cluster\n• Hard Multi-tenancy: Untrusted tenants, strong isolation\n• Cluster-per-tenant: Ultimate isolation\n\nResource Isolation:\n• ResourceQuotas: Limit resource consumption\n• LimitRanges: Default and maximum resource limits\n• PodSecurityPolicies: Security constraints\n• NetworkPolicies: Network traffic isolation\n\nExample ResourceQuota:\napiVersion: v1\nkind: ResourceQuota\nmetadata:\n name: tenant-quota\n namespace: tenant-a\nspec:\n hard:\n requests.cpu: "4"\n requests.memory: 8Gi\n limits.cpu: "8"\n limits.memory: 16Gi\n pods: "10"\n services: "5"\n\nExample NetworkPolicy:\napiVersion: networking.k8s.io/v1\nkind: NetworkPolicy\nmetadata:\n name: tenant-isolation\n namespace: tenant-a\nspec:\n podSelector: {}\n policyTypes:\n - Ingress\n - Egress\n ingress:\n - from:\n - namespaceSelector:\n matchLabels:\n name: tenant-a\n\nBest Practices:\n• Use admission controllers for policy enforcement\n• Implement monitoring per tenant\n• Regular security audits\n• Automate tenant provisioning\n• Consider virtual clusters for stronger isolation