Azure Key Vault CSI Driver Skill

Overview

This skill provides guidance for integrating Azure Key Vault with Kubernetes using the Secrets Store CSI Driver. All sensitive data in the Hypera clusters is stored in Azure Key Vault and accessed via the CSI driver.

Quick Reference

Environment Configuration

SecretProviderClass Template

apiVersion: secrets-store.csi.x-k8s.io/v1
kind: SecretProviderClass
metadata:
  name: <app>-secrets
  namespace: <namespace>
  labels:
    app.kubernetes.io/name: <app>
    app.kubernetes.io/component: secrets
spec:
  provider: azure
  parameters:
    usePodIdentity: "false"
    useVMManagedIdentity: "true"
    userAssignedIdentityID: "<managed-identity-client-id>"
    keyvaultName: "<keyvault-name>"
    cloudName: "AzurePublicCloud"
    tenantId: "<tenant-id>"
    objects: |
      array:
        - |
          objectName: "<secret-name-in-keyvault>"
          objectType: "secret"
          objectAlias: "<ALIAS_FOR_MOUNT>"
  # Optional: Sync to Kubernetes Secret
  secretObjects:
    - secretName: <k8s-secret-name>
      type: Opaque
      data:
        - objectName: "<ALIAS_FOR_MOUNT>"
          key: "<key-in-k8s-secret>"

Pod Volume Mount

spec:
  containers:
    - name: app
      volumeMounts:
        - name: secrets-store
          mountPath: "/mnt/secrets-store"
          readOnly: true
  volumes:
    - name: secrets-store
      csi:
        driver: secrets-store.csi.k8s.io
        readOnly: true
        volumeAttributes:
          secretProviderClass: "<secretproviderclass-name>"

Common Patterns

Pattern 1: Simple API Token (e.g., Cloudflare)

apiVersion: secrets-store.csi.x-k8s.io/v1
kind: SecretProviderClass
metadata:
  name: cloudflare-api-token-kv
  namespace: external-dns
spec:
  provider: azure
  secretObjects:
    - data:
        - key: cloudflare_api_token
          objectName: cloudflare-api-token
      secretName: cloudflare-api-token
      type: Opaque
  parameters:
    usePodIdentity: "false"
    useVMManagedIdentity: "true"
    userAssignedIdentityID: "f1a14a8f-6d38-40a0-a935-3cdd91a25f47"
    keyvaultName: "kv-cafehyna-dev-hlg"
    objects: |
      array:
        - |
          objectName: cloudflare-api-token
          objectType: secret
    tenantId: "3f7a3df4-f85b-4ca8-98d0-08b1034e6567"

Pattern 2: Multiple Secrets to Multiple K8s Secrets

apiVersion: secrets-store.csi.x-k8s.io/v1
kind: SecretProviderClass
metadata:
  name: app-secrets
spec:
  provider: azure
  parameters:
    usePodIdentity: "false"
    useVMManagedIdentity: "true"
    userAssignedIdentityID: "<identity>"
    keyvaultName: "<keyvault>"
    tenantId: "<tenant>"
    objects: |
      array:
        - |
          objectName: "app-db-password"
          objectType: "secret"
          objectAlias: "DB_PASSWORD"
        - |
          objectName: "app-redis-password"
          objectType: "secret"
          objectAlias: "REDIS_PASSWORD"
  secretObjects:
    - secretName: app-db-secret
      type: Opaque
      data:
        - objectName: "DB_PASSWORD"
          key: "password"
    - secretName: app-redis-secret
      type: Opaque
      data:
        - objectName: "REDIS_PASSWORD"
          key: "password"

Pattern 3: TLS Certificate

apiVersion: secrets-store.csi.x-k8s.io/v1
kind: SecretProviderClass
metadata:
  name: tls-cert-provider
spec:
  provider: azure
  secretObjects:
    - secretName: tls-secret
      type: kubernetes.io/tls
      data:
        - objectName: tls-cert
          key: tls.crt
        - objectName: tls-key
          key: tls.key
  parameters:
    usePodIdentity: "false"
    useVMManagedIdentity: "true"
    userAssignedIdentityID: "<identity>"
    keyvaultName: "<keyvault>"
    tenantId: "<tenant>"
    objects: |
      array:
        - |
          objectName: my-certificate
          objectType: cert
          objectAlias: tls-cert
        - |
          objectName: my-certificate
          objectType: secret
          objectAlias: tls-key

File Locations

SecretProviderClass files are stored in:

argo-cd-helm-values/kube-addons/<application>/<cluster>/secretproviderclass.yaml

Examples:

• argo-cd-helm-values/kube-addons/defectdojo/cafehyna-dev/secretproviderclass.yaml
• argo-cd-helm-values/kube-addons/external-dns/cafehyna-dev/secretproviderclass.yaml
• argo-cd-helm-values/kube-addons/cert-manager/cafehyna-dev/csi-cloudflare-api-key.yaml

Troubleshooting

Error: 403 Forbidden

Cause: Managed identity lacks Key Vault permissions.

Solution:

# Get identity info from error message, then:
az keyvault set-policy \
  --name "<keyvault-name>" \
  --object-id "<object-id-from-error>" \
  --secret-permissions get list

# Or for RBAC-enabled Key Vaults:
az role assignment create \
  --role "Key Vault Secrets User" \
  --assignee-object-id "<object-id>" \
  --assignee-principal-type ServicePrincipal \
  --scope "/subscriptions/.../Microsoft.KeyVault/vaults/<kv-name>"

Error: Secret Not Found

Cause: Secret name doesn't exist or case mismatch.

Solution:

# List secrets (names are case-sensitive)
az keyvault secret list --vault-name "<kv-name>" --query "[].name" -o tsv

Error: K8s Secret Not Created

Cause: No pod has mounted the CSI volume yet.

Solution: Deploy a pod that mounts the volume. K8s secrets are only created when at least one pod uses the SecretProviderClass.

Error: Pod Stuck in ContainerCreating

Diagnostic:

kubectl describe pod <pod-name> -n <namespace>
kubectl get pods -n kube-system | grep secrets-store
kubectl logs -n kube-system -l app=secrets-store-provider-azure

Scripts

Grant Key Vault Permissions

# Use the helper script
./scripts/grant-keyvault-permissions.sh

# Or quick manual command
az keyvault set-policy \
  --name "kv-cafehyna-dev-hlg" \
  --object-id "<object-id>" \
  --secret-permissions get list

Create Secret in Key Vault

az keyvault secret set \
  --vault-name "kv-cafehyna-dev-hlg" \
  --name "my-app-secret" \
  --value "secret-value"

List All SecretProviderClasses

kubectl get secretproviderclass -A

Check CSI Driver Status

kubectl get pods -n kube-system | grep secrets-store

Important Notes

1. CSI Volume Required: Even if using secretObjects to sync to K8s secrets, the pod MUST mount the CSI volume.

2. Secret Names: Key Vault secret names are case-sensitive. Use exact match.

3. Object Alias: Use objectAlias for filesystem-safe names when mounting.

4. Namespace Scope: SecretProviderClass is namespace-scoped. Create one per namespace that needs it.

5. RBAC vs Access Policies: Check Key Vault authorization model:

   az keyvault show --name "<kv>" --query "properties.enableRbacAuthorization"
   

Detailed Reference

For complete implementation examples and architecture:

• references/architecture.md - CSI driver architecture
• references/examples.md - Real-world examples
• references/troubleshooting.md - Extended troubleshooting