Q: Your security compliance policy forbids storing plaintext secrets in Git and requires all database credentials in Azure Key Vault to be rotated every 90 days. How do you implement the Secrets Store CSI Driver on AKS with Azure AD Workload Identity and automated rotation without restarting application pods?
Production guide for synchronizing Azure Key Vault secrets, keys, and certificates into AKS pods using the Secrets Store CSI Driver with auto-rotation and Kubernetes secret mirroring.
#Azure #Key Vault #CSI Driver #AKS #Secrets Management #Auto-Rotation
🎙️ Candidate Opening & Architectural Context
"Developers previously copied secrets from Azure Key Vault into static Kubernetes Secret manifests. When Key Vault secrets rotated, pods continued using stale credentials until manual pod restarts were executed. We deployed the native Azure Key Vault Secrets Store CSI Driver with auto-rotation enabled."
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🛠️ Production Runbook & Step-by-Step Resolution
1️⃣
Enable Secrets Store CSI Driver Add-on on AKS
Activate the managed Kubernetes CSI driver and autorotation feature:
- Enable Add-on: Executed
az aks enable-addons --addons azure-keyvault-secrets-provider --name aks-prod --resource-group rg-aks. - Enable Auto-Rotation: Updated cluster with
az aks update -g rg-aks -n aks-prod --enable-secret-rotation --rotation-poll-interval 2m.
Pro Tip: The rotation poll interval determines how frequently the CSI driver queries Azure Key Vault for updated secret versions (default 2 minutes).
2️⃣
Create SecretProviderClass Manifest with Workload Identity
Define which secrets to pull from Key Vault and bind to Azure AD identity:
- SecretProviderClass CRD: Defined
SecretProviderClassdeclaringusePodIdentity: 'false',clientID: $MANAGED_IDENTITY_CLIENT_ID, and listing secret objects (db-password,api-token). - Secret Mirroring: Configured
secretObjectsblock to automatically generate a native Kubernetes Secret for workloads that consume secrets via environment variables.
Pro Tip: Secrets are mounted directly as in-memory tmpfs files into the pod, avoiding writing secrets to physical node disk storage.
3️⃣
Mount CSI Volume into Application Pod Deployment
Attach the secret volume to the application container filesystem:
- Pod Volume: Configured
volumes: [ { name: 'secrets-store', csi: { driver: 'secrets-store.csi.k8s.io', readOnly: true, volumeAttributes: { secretProviderClass: 'azure-kv-provider' } } } ]. - VolumeMount: Mounted volume at
/mnt/secrets-storeinside the application container.
Pro Tip: The CSI driver fetches secrets from Azure Key Vault only when a pod referencing the SecretProviderClass is actively being scheduled.
4️⃣
Handle Dynamic In-Pod Credential Rotation
Ensure application processes detect updated secret files on disk without container restarts:
- File Watcher: Updated application code with an in-memory file watcher (e.g., inotify/chokidar) listening for changes on
/mnt/secrets-store/db-password. - Reloader Controller: Alternatively deployed Stakater Reloader to trigger a rolling pod restart if native file watching is not supported by legacy frameworks.
Pro Tip: File watcher patterns allow zero-downtime database connection pool refreshes without interrupting active user traffic.
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Secrets Store CSI Driver with Azure Key Vault integration eliminates hardcoded credentials, mounts secrets as secure memory files, and continuously auto-rotates secrets across AKS workloads."
⚡ 60-Second Elevator Pitch Talking Points
- Enable Azure Key Vault Secrets Provider add-on with --enable-secret-rotation on AKS.
- Authenticate pods to Key Vault using Azure AD Workload Identity with zero stored credentials.
- Mount secrets directly into memory tmpfs volumes via SecretProviderClass manifests.
- Use in-app file watchers or Reloader to pick up rotated credentials with zero application downtime.
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