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Azure CLI - Restrict import/export access for managed disks with Private Links

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Applies to: ✔️ Linux VMs ✔️ Flexible scale sets

You can use private endpoints to restrict the export and import of managed disks and securely access data over a Private Link from clients on your Azure virtual network. The private endpoint uses an IP address from the virtual network address space for your managed disks service. Network traffic between clients on their virtual network and managed disks only traverses over the virtual network and a private link on the Microsoft backbone network, eliminating exposure from the public internet.

To use Private Links to export/import managed disks, first you create a disk access resource and link it to a virtual network in the same subscription by creating a private endpoint. Then, associate a disk or a snapshot with an instance of disk access. Finally, set the NetworkAccessPolicy property of the disk or the snapshot to AllowPrivate. This will limit access to your virtual network.

You can set the NetworkAccessPolicy property to DenyAll to prevent anybody from exporting data of a disk or a snapshot. The default value for the NetworkAccessPolicy property is AllowAll.

Limitations

  • You can't import or export more than five disks or snapshots at the same time with the same disk access object.
  • You can't upload to a disk with both a disk access object and a disk encryption set.

Log in into your subscription and set your variables

subscriptionId=yourSubscriptionId
resourceGroupName=yourResourceGroupName
region=northcentralus
diskAccessName=yourDiskAccessForPrivateLinks
vnetName=yourVNETForPrivateLinks
subnetName=yourSubnetForPrivateLinks
privateEndPointName=yourPrivateLinkForSecureMDExportImport
privateEndPointConnectionName=yourPrivateLinkConnection

#The name of an existing disk which is the source of the snapshot
sourceDiskName=yourSourceDiskForSnapshot

#The name of the new snapshot which will be secured via Private Links
snapshotNameSecuredWithPL=yourSnapshotNameSecuredWithPL

az login

az account set --subscription $subscriptionId

Create a disk access using Azure CLI

az disk-access create -n $diskAccessName -g $resourceGroupName -l $region

diskAccessId=$(az disk-access show -n $diskAccessName -g $resourceGroupName --query [id] -o tsv)

Create a Virtual Network

Network policies like network security groups (NSG) are not supported for private endpoints. In order to deploy a Private Endpoint on a given subnet, an explicit disable setting is required on that subnet.

az network vnet create --resource-group $resourceGroupName \
    --name $vnetName \
    --subnet-name $subnetName

Disable subnet private endpoint policies

Azure deploys resources to a subnet within a virtual network, so you need to update the subnet to disable private endpoint network policies.

az network vnet subnet update --resource-group $resourceGroupName \
    --name $subnetName  \
    --vnet-name $vnetName \
    --disable-private-endpoint-network-policies true

Create a private endpoint for the disk access object

az network private-endpoint create --resource-group $resourceGroupName \
    --name $privateEndPointName \
    --vnet-name $vnetName  \
    --subnet $subnetName \
    --private-connection-resource-id $diskAccessId \
    --group-ids disks \
    --connection-name $privateEndPointConnectionName

Configure the Private DNS Zone

Create a Private DNS Zone for Storage blob domain, create an association link with the Virtual Network and create a DNS Zone Group to associate the private endpoint with the Private DNS Zone.

az network private-dns zone create --resource-group $resourceGroupName \
    --name "privatelink.blob.core.windows.net"

az network private-dns link vnet create --resource-group $resourceGroupName \
    --zone-name "privatelink.blob.core.windows.net" \
    --name yourDNSLink \
    --virtual-network $vnetName \
    --registration-enabled false 

az network private-endpoint dns-zone-group create \
   --resource-group $resourceGroupName \
   --endpoint-name $privateEndPointName \
   --name yourZoneGroup \
   --private-dns-zone "privatelink.blob.core.windows.net" \
   --zone-name disks

resourceGroupName=yourResourceGroupName
region=northcentralus
diskAccessName=yourDiskAccessName
diskName=yourDiskName
diskSkuName=Standard_LRS
diskSizeGB=128

diskAccessId=$(az resource show -n $diskAccessName -g $resourceGroupName --namespace Microsoft.Compute --resource-type diskAccesses --query [id] -o tsv)

az disk create -n $diskName \
-g $resourceGroupName \
-l $region \
--size-gb $diskSizeGB \
--sku $diskSkuName \
--network-access-policy AllowPrivate \
--disk-access $diskAccessId 

resourceGroupName=yourResourceGroupName
region=northcentralus
diskAccessName=yourDiskAccessName
sourceDiskName=yourSourceDiskForSnapshot
snapshotNameSecuredWithPL=yourSnapshotName

diskId=$(az disk show -n $sourceDiskName -g $resourceGroupName --query [id] -o tsv)

diskAccessId=$(az resource show -n $diskAccessName -g $resourceGroupName --namespace Microsoft.Compute --resource-type diskAccesses --query [id] -o tsv)

az snapshot create -n $snapshotNameSecuredWithPL \
-g $resourceGroupName \
-l $region \
--source $diskId \
--network-access-policy AllowPrivate \
--disk-access $diskAccessId

Next steps