dhaneshuk presents a thorough walkthrough for building and operating enterprise-grade, multi-tenant AKS clusters, highlighting security, DevOps, cost optimization, and operational know-how for Microsoft consultants and developers.

Building Enterprise-Grade Shared AKS Clusters: Multi-Tenant Kubernetes Architecture

dhaneshuk offers a deep-dive guide to architecting and running shared Azure Kubernetes Service (AKS) clusters for large teams. The walkthrough covers architectural principles, multi-tenancy mechanisms (namespaces, RBAC, policies), operational best practices, security controls, CI/CD, disaster recovery, detailed Kubernetes/YAML samples, and cost/billing strategies—all mapped to Microsoft Azure’s platform features and tooling.

1. Shared AKS Architecture

  • One AKS cluster per environment (prod/test/dev).
  • Business units share clusters by isolated namespaces.
  • Platform-wide services (ingress, cert management, monitoring, backup) run in a dedicated namespace.
  • Network isolation through Azure CNI; RBAC enforced via Azure AD.
  • Namespace quotas, pod security, and trusted container sources (ACR) maximize security and reliability.

Multi-Tenancy Mechanisms:

  • Namespaces: team/app isolation
  • RBAC: Azure AD integration for precise access
  • NetworkPolicy: control east-west traffic
  • Quotas/LimitRange to prevent overuse
  • Admission policies for pod security and image trust

Why Per-Environment Clusters?

  • Reduced blast radius
  • Simpler lifecycle and audit separation
  • Isolated scaling and compliance

Network Isolation

  • Azure CNI assigns real VNet IPs to pods
  • Subnet separation for system/workload/batch pools
  • Private clusters restrict API exposure

2. Key Platform Components

  • Autoscaling: Cluster Autoscaler, HPA, VPA, KEDA (Azure-native + event-driven)
  • Service Mesh: Optional (Istio/Ambient Mesh) for mTLS, traffic control—only if needed
  • Ingress & TLS: NGINX or Azure Application Gateway with cert-manager (Key Vault for secrets)
  • Secrets: Key Vault via CSI driver, sealed-secrets for special cases, External Secrets Operator
  • Storage: Azure Disk (IOPS), Azure Files (shared), NetApp Files, Blob Storage for backup
  • Backups: Velero backup/restore, Blob Storage, IaC for DR
  • Observability: Prometheus (metrics), Grafana, Azure Monitor, OpenTelemetry tracing

3. CI/CD Strategy

  • Declarative deployments via Helm or Kustomize, all manifests in Git
  • Pipelines per application/environment with image build, scan (Trivy, Defender), sign (Cosign)
  • GitOps controllers (Flux/ArgoCD) for applying manifests/Helm charts
  • Secrets never in Git—sourced dynamically via Key Vault
  • Promotion between environments reuses the exact image digest

Sample GitHub Actions Snippet:

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Login ACR
        uses: azure/docker-login@v1
        with:
          login-server: $.azurecr.io
          username: $
          password: $
      - name: Build
        run: docker build -t $.azurecr.io/payments:$ .
      - name: Scan
        uses: aquasecurity/trivy-action@v0.13.0
        with:
          image-ref: $.azurecr.io/payments:$
          severity: HIGH,CRITICAL
      - name: Push
        run: docker push $.azurecr.io/payments:$

4. Backup & Disaster Recovery

  • Backups: Velero for cluster/PV; store in Azure Blob with versioning/lifecycle
  • DR: Recreate cluster with Bicep/Terraform, restore from backup via Velero, bootstrap with GitOps
  • Testing: Monthly restores to ephemeral cluster, validate apps/data

5. Operational Insights

  • Resource optimization: VPA for tuning, KEDA for bursty/batch workloads, spot instances for batch
  • Quotas & priorities protect against noisy neighbors
  • Operational dashboards track node/capacity/latency/SLOs
  • Playbooks provided for incident response and postmortems

6. Cost & Billing

  • Label/tag Azure resources and namespaces for allocation
  • Use Kubecost/Azure Advisor for cost tracking
  • Optimization: Rightsizing, spot nodes, autoscaling, tiered storage
  • Chargeback/showback with monthly reporting per namespace

7. Security & Compliance

  • Layered model: Azure AD RBAC, pod security, network isolation, supply chain security (Cosign, ACR), secrets management (Key Vault), runtime defense (Defender)
  • GitOps repo as source of truth for RBAC roles and all cluster configuration
  • Compliance mapped explicitly: encryption, audit, vulnerability scans
  • YAML samples for RBAC, NetworkPolicy, SecretProviders

8. Monitoring & Observability

  • Metrics: Prometheus; Logs: Azure Monitor; Traces: OpenTelemetry
  • Alerting best practices: page on SLO breach, ticket on trends
  • Sample dashboards and log retention strategy (30-180 days)

9. Hands-On Lab

  • Guided CLI/Helm workflows for AKS resource creation, service deployment, backup, monitoring, scaling, cost tooling, cleanup
  • Validates end-to-end: from initial cluster to app deployment, scaling under load, snapshot/restore, and resource teardown

10. Next Steps

  • Add full GitOps bootstrap
  • Namespace-level network policies
  • Integrate image signing enforcement

Last updated Nov 10, 2025.

Author: dhaneshuk

This post appeared first on “Microsoft Tech Community”. Read the entire article here