Create and use a volume with Azure Blob storage in Azure Kubernetes Service (AKS)
Container-based applications often need to access and persist data in an external data volume. If multiple pods need concurrent access to the same storage volume, you can use Azure Blob storage to connect using blobfuse or Network File System (NFS).
This article shows you how to:
- Work with a dynamic persistent volume (PV) by installing the Container Storage Interface (CSI) driver and dynamically creating an Azure Blob storage container to attach to a pod.
- Work with a static PV by creating an Azure Blob storage container, or use an existing one and attach it to a pod.
For more information on Kubernetes volumes, see Storage options for applications in AKS.
Before you begin
Enable the Blob storage CSI driver on your AKS cluster.
To support an Azure DataLake Gen2 storage account when using blobfuse mount, you'll need to do the following:
- To create an ADLS account using the driver in dynamic provisioning, specify
isHnsEnabled: "true"in the storage class parameters. - To enable blobfuse access to an ADLS account in static provisioning, specify the mount option
--use-adls=truein the persistent volume. - If you are going to enable a storage account with Hierarchical Namespace, existing persistent volumes should be remounted with
--use-adls=truemount option.
- To create an ADLS account using the driver in dynamic provisioning, specify
About blobfuse cache
- By default, the blobfuse cache is located in the
/mntdirectory. If the VM SKU provides a temporary disk, the/mntdirectory is mounted on the temporary disk. However, if the VM SKU does not provide a temporary disk, the/mntdirectory is mounted on the OS disk, you could set--tmp-path=mount option to specify a different cache directory
- By default, the blobfuse cache is located in the
Dynamically provision a volume
This section provides guidance for cluster administrators who want to provision one or more persistent volumes that include details of Blob storage for use by a workload. A persistent volume claim (PVC) uses the storage class object to dynamically provision an Azure Blob storage container.
Storage class parameters for dynamic persistent volumes
The following table includes parameters you can use to define a custom storage class for your persistent volume claim.
| Name | Description | Example | Mandatory | Default value |
|---|---|---|---|---|
| skuName | Specify an Azure storage account type (alias: storageAccountType). |
Standard_LRS, Premium_LRS, Standard_GRS, Standard_RAGRS |
No | Standard_LRS |
| location | Specify an Azure location. | eastus |
No | If empty, driver will use the same location name as current cluster. |
| resourceGroup | Specify an Azure resource group name. | myResourceGroup | No | If empty, driver will use the same resource group name as current cluster. |
| storageAccount | Specify an Azure storage account name. | storageAccountName | - No | When a specific storage account name is not provided, the driver will look for a suitable storage account that matches the account settings within the same resource group. If it fails to find a matching storage account, it will create a new one. However, if a storage account name is specified, the storage account must already exist. |
| networkEndpointType | Specify network endpoint type for the storage account created by driver. If privateEndpoint is specified, a private endpoint is created for the storage account. For other cases, a service endpoint will be created for NFS protocol.1 | privateEndpoint |
No | For an AKS cluster, add the AKS cluster name to the Contributor role in the resource group hosting the VNET. |
| protocol | Specify blobfuse mount or NFSv3 mount. | fuse, nfs |
No | fuse |
| containerName | Specify the existing container (directory) name. | container | No | If empty, driver creates a new container name, starting with pvc-fuse for blobfuse or pvc-nfs for NFS v3. |
| containerNamePrefix | Specify Azure storage directory prefix created by driver. | my | Can only contain lowercase letters, numbers, hyphens, and length should be fewer than 21 characters. | No |
| server | Specify Azure storage account domain name. | Existing storage account DNS domain name, for example <storage-account>.privatelink.blob.core.windows.net. |
No | If empty, driver uses default <storage-account>.blob.core.windows.net or other sovereign cloud storage account DNS domain name. |
| allowBlobPublicAccess | Allow or disallow public access to all blobs or containers for storage account created by driver. | true,false |
No | false |
| storageEndpointSuffix | Specify Azure storage endpoint suffix. | core.windows.net |
No | If empty, driver will use default storage endpoint suffix according to cloud environment. |
| tags | Tags would be created in new storage account. | Tag format: 'foo=aaa,bar=bbb' | No | "" |
| matchTags | Match tags when driver tries to find a suitable storage account. | true,false |
No | false |
| --- | Following parameters are only for blobfuse | --- | --- | --- |
| subscriptionID | Specify Azure subscription ID where blob storage directory will be created. | Azure subscription ID | No | If not empty, resourceGroup must be provided. |
| storeAccountKey | Specify store account key to Kubernetes secret. Note: false means driver uses kubelet identity to get account key. |
true,false |
No | true |
| secretName | Specify secret name to store account key. | No | ||
| secretNamespace | Specify the namespace of secret to store account key. | default,kube-system, etc. |
No | pvc namespace |
| isHnsEnabled | Enable Hierarchical namespace for Azure Data Lake storage account. |
true,false |
No | false |
| --- | Following parameters are only for NFS protocol | --- | --- | --- |
| mountPermissions | Specify mounted folder permissions. | The default is 0777. If set to 0, driver won't perform chmod after mount. |
0777 |
No |
1 If the storage account is created by the driver, then you only need to specify networkEndpointType: privateEndpoint parameter in storage class. The CSI driver creates the private endpoint together with the account. If you bring your own storage account, then you need to create the private endpoint for the storage account.
Create a persistent volume claim using built-in storage class
A persistent volume claim (PVC) uses the storage class object to dynamically provision an Azure Blob storage container. The following YAML can be used to create a persistent volume claim 5 GB in size with ReadWriteMany access, using the built-in storage class. For more information on access modes, see the Kubernetes persistent volume documentation.
Create a file named
blob-nfs-pvc.yamland copy in the following YAML.apiVersion: v1 kind: PersistentVolumeClaim metadata: name: azure-blob-storage spec: accessModes: - ReadWriteMany storageClassName: azureblob-nfs-premium resources: requests: storage: 5GiCreate the persistent volume claim with the kubectl create command:
kubectl create -f blob-nfs-pvc.yaml
Once completed, the Blob storage container will be created. You can use the kubectl get command to view the status of the PVC:
kubectl get pvc azure-blob-storage
The output of the command resembles the following example:
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
azure-blob-storage Bound pvc-b88e36c5-c518-4d38-a5ee-337a7dda0a68 5Gi RWX azureblob-nfs-premium 92m
Use the persistent volume claim
The following YAML creates a pod that uses the persistent volume claim azure-blob-storage to mount the Azure Blob storage at the `/mnt/blob' path.
Create a file named
blob-nfs-pv, and copy in the following YAML. Make sure that the claimName matches the PVC created in the previous step.kind: Pod apiVersion: v1 metadata: name: mypod spec: containers: - name: mypod image: mcr.microsoft.com/oss/nginx/nginx:1.17.3-alpine resources: requests: cpu: 100m memory: 128Mi limits: cpu: 250m memory: 256Mi volumeMounts: - mountPath: "/mnt/blob" name: volume readOnly: false volumes: - name: volume persistentVolumeClaim: claimName: azure-blob-storageCreate the pod with the kubectl apply command:
kubectl apply -f blob-nfs-pv.yamlAfter the pod is in the running state, run the following command to create a new file called
test.txt.kubectl exec mypod -- touch /mnt/blob/test.txtTo validate the disk is correctly mounted, run the following command, and verify you see the
test.txtfile in the output:kubectl exec mypod -- ls /mnt/blobThe output of the command resembles the following example:
test.txt
Create a custom storage class
The default storage classes suit the most common scenarios, but not all. In some cases you might want to have your own storage class customized with your own parameters. In this section, we provide two examples. The first one uses the NFS protocol, and the second one uses blobfuse.
Storage class using NFS protocol
In this example, the following manifest configures mounting a Blob storage container using the NFS protocol. Use it to add the tags parameter.
Create a file named
blob-nfs-sc.yaml, and paste the following example manifest:apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: azureblob-nfs-premium provisioner: blob.csi.azure.com parameters: protocol: nfs tags: environment=Development volumeBindingMode: Immediate allowVolumeExpansion: true mountOptions: - nconnect=4Create the storage class with the kubectl apply command:
kubectl apply -f blob-nfs-sc.yamlThe output of the command resembles the following example:
storageclass.storage.k8s.io/blob-nfs-premium created
Storage class using blobfuse
In this example, the following manifest configures using blobfuse and mounts a Blob storage container. Use it to update the skuName parameter.
Create a file named
blobfuse-sc.yaml, and paste the following example manifest:apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: azureblob-fuse-premium provisioner: blob.csi.azure.com parameters: skuName: Standard_GRS # available values: Standard_LRS, Premium_LRS, Standard_GRS, Standard_RAGRS reclaimPolicy: Delete volumeBindingMode: Immediate allowVolumeExpansion: true mountOptions: - -o allow_other - --file-cache-timeout-in-seconds=120 - --use-attr-cache=true - --cancel-list-on-mount-seconds=10 # prevent billing charges on mounting - -o attr_timeout=120 - -o entry_timeout=120 - -o negative_timeout=120 - --log-level=LOG_WARNING # LOG_WARNING, LOG_INFO, LOG_DEBUG - --cache-size-mb=1000 # Default will be 80% of available memory, eviction will happen beyond that.Create the storage class with the kubectl apply command:
kubectl apply -f blobfuse-sc.yamlThe output of the command resembles the following example:
storageclass.storage.k8s.io/blob-fuse-premium created
Statically provision a volume
This section provides guidance for cluster administrators who want to create one or more persistent volumes that include details of Blob storage for use by a workload.
Static provisioning parameters for persistent volumes
The following table includes parameters you can use to define a persistent volume.
| Name | Description | Example | Mandatory | Default value |
|---|---|---|---|---|
| volumeHandle | Specify a value the driver can use to uniquely identify the storage blob container in the cluster. | A recommended way to produce a unique value is to combine the globally unique storage account name and container name: {account-name}_{container-name}.Note: The #, / character are reserved for internal use and can't be used in a volume handle. |
Yes | |
| volumeAttributes.resourceGroup | Specify Azure resource group name. | myResourceGroup | No | If empty, driver uses the same resource group name as current cluster. |
| volumeAttributes.storageAccount | Specify an existing Azure storage account name. | storageAccountName | Yes | |
| volumeAttributes.containerName | Specify existing container name. | container | Yes | |
| volumeAttributes.protocol | Specify blobfuse mount or NFS v3 mount. | fuse, nfs |
No | fuse |
| --- | Following parameters are only for blobfuse | --- | --- | --- |
| volumeAttributes.secretName | Secret name that stores storage account name and key (only applies for SMB). | No | ||
| volumeAttributes.secretNamespace | Specify namespace of secret to store account key. | default |
No | Pvc namespace |
| nodeStageSecretRef.name | Specify secret name that stores one of the following:azurestorageaccountkeyazurestorageaccountsastokenmsisecretazurestoragespnclientsecret. |
No | Existing Kubernetes secret name | |
| nodeStageSecretRef.namespace | Specify the namespace of secret. | Kubernetes namespace | Yes | |
| --- | Following parameters are only for NFS protocol | --- | --- | --- |
| volumeAttributes.mountPermissions | Specify mounted folder permissions. | 0777 |
No | |
| --- | Following parameters are only for NFS VNet setting | --- | --- | --- |
| vnetResourceGroup | Specify VNet resource group hosting virtual network. | myResourceGroup | No | If empty, driver uses the vnetResourceGroup value specified in the Azure cloud config file. |
| vnetName | Specify the virtual network name. | aksVNet | No | If empty, driver uses the vnetName value specified in the Azure cloud config file. |
| subnetName | Specify the existing subnet name of the agent node. | aksSubnet | No | If empty, driver uses the subnetName value in Azure cloud config file. |
| --- | Following parameters are only for feature: blobfuse Managed Identity and Service Principal Name authentication |
--- | --- | --- |
| volumeAttributes.AzureStorageAuthType | Specify the authentication type. | Key, SAS, MSI, SPN |
No | Key |
| volumeAttributes.AzureStorageIdentityClientID | Specify the Identity Client ID. | No | ||
| volumeAttributes.AzureStorageIdentityResourceID | Specify the Identity Resource ID. | No | ||
| volumeAttributes.MSIEndpoint | Specify the MSI endpoint. | No | ||
| volumeAttributes.AzureStorageSPNClientID | Specify the Azure Service Principal Name (SPN) Client ID. | No | ||
| volumeAttributes.AzureStorageSPNTenantID | Specify the Azure SPN Tenant ID. | No | ||
| volumeAttributes.AzureStorageAADEndpoint | Specify the Microsoft Entra endpoint. | No | ||
| --- | Following parameters are only for feature: blobfuse read account key or SAS token from key vault | --- | --- | --- |
| volumeAttributes.keyVaultURL | Specify Azure Key Vault DNS name. | {vault-name}.vault.azure.net | No | |
| volumeAttributes.keyVaultSecretName | Specify Azure Key Vault secret name. | Existing Azure Key Vault secret name. | No | |
| volumeAttributes.keyVaultSecretVersion | Azure Key Vault secret version. | Existing version | No | If empty, driver uses current version. |
Create a Blob storage container
When you create an Azure Blob storage resource for use with AKS, you can create the resource in the node resource group. This approach allows the AKS cluster to access and manage the blob storage resource.
For this article, create the container in the node resource group. First, get the resource group name with the az aks show command and add the --query nodeResourceGroup query parameter. The following example gets the node resource group for the AKS cluster named myAKSCluster in the resource group named myResourceGroup:
az aks show --resource-group myResourceGroup --name myAKSCluster --query nodeResourceGroup -o tsv
The output of the command resembles the following example:
MC_myResourceGroup_myAKSCluster_eastus
Next, create a container for storing blobs following the steps in the Manage blob storage to authorize access and then create the container.
Mount volume
In this section, you mount the persistent volume using the NFS protocol or Blobfuse.
Mounting Blob storage using the NFS v3 protocol doesn't authenticate using an account key. Your AKS cluster needs to reside in the same or peered virtual network as the agent node. The only way to secure the data in your storage account is by using a virtual network and other network security settings. For more information on how to set up NFS access to your storage account, see Mount Blob Storage by using the Network File System (NFS) 3.0 protocol.
The following example demonstrates how to mount a Blob storage container as a persistent volume using the NFS protocol.
Create a file named
pv-blob-nfs.yamland copy in the following YAML. UnderstorageClass, updateresourceGroup,storageAccount, andcontainerName.Note
volumeHandlevalue should be a unique volumeID for every identical storage blob container in the cluster. The character#and/are reserved for internal use and cannot be used.apiVersion: v1 kind: PersistentVolume metadata: annotations: pv.kubernetes.io/provisioned-by: blob.csi.azure.com name: pv-blob spec: capacity: storage: 1Pi accessModes: - ReadWriteMany persistentVolumeReclaimPolicy: Retain # If set as "Delete" container would be removed after pvc deletion storageClassName: azureblob-nfs-premium mountOptions: - nconnect=4 csi: driver: blob.csi.azure.com # make sure volumeid is unique for every identical storage blob container in the cluster # character `#` and `/` are reserved for internal use and cannot be used in volumehandle volumeHandle: account-name_container-name volumeAttributes: resourceGroup: resourceGroupName storageAccount: storageAccountName containerName: containerName protocol: nfsNote
While the Kubernetes API capacity attribute is mandatory, this value isn't used by the Azure Blob storage CSI driver because you can flexibly write data until you reach your storage account's capacity limit. The value of the
capacityattribute is used only for size matching between PersistentVolumes and PersistentVolumeClaims. We recommend using a fictitious high value. The pod sees a mounted volume with a fictitious size of 5 Petabytes.Run the following command to create the persistent volume using the kubectl create command referencing the YAML file created earlier:
kubectl create -f pv-blob-nfs.yamlCreate a
pvc-blob-nfs.yamlfile with a PersistentVolumeClaim. For example:kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pvc-blob spec: accessModes: - ReadWriteMany resources: requests: storage: 10Gi volumeName: pv-blob storageClassName: azureblob-nfs-premiumRun the following command to create the persistent volume claim using the kubectl create command referencing the YAML file created earlier:
kubectl create -f pvc-blob-nfs.yaml
Use the persistent volume
The following YAML creates a pod that uses the persistent volume or persistent volume claim named pvc-blob created earlier, to mount the Azure Blob storage at the /mnt/blob path.
Create a file named
nginx-pod-blob.yaml, and copy in the following YAML. Make sure that the claimName matches the PVC created in the previous step when creating a persistent volume for NFS or Blobfuse.kind: Pod apiVersion: v1 metadata: name: nginx-blob spec: nodeSelector: "kubernetes.io/os": linux containers: - image: mcr.microsoft.com/oss/nginx/nginx:1.17.3-alpine name: nginx-blob volumeMounts: - name: blob01 mountPath: "/mnt/blob" readOnly: false volumes: - name: blob01 persistentVolumeClaim: claimName: pvc-blobRun the following command to create the pod and mount the PVC using the kubectl create command referencing the YAML file created earlier:
kubectl create -f nginx-pod-blob.yamlRun the following command to create an interactive shell session with the pod to verify the Blob storage mounted:
kubectl exec -it nginx-blob -- df -hThe output from the command resembles the following example:
Filesystem Size Used Avail Use% Mounted on ... blobfuse 14G 41M 13G 1% /mnt/blob ...
Next steps
- To learn how to use CSI driver for Azure Blob storage, see Use Azure Blob storage with CSI driver.
- For associated best practices, see Best practices for storage and backups in AKS.
Azure Kubernetes Service