Disable vhd delete when using managed disks

Disabled logic for deleting vhd and storageaccount create/delete
when using managed disks. Prior, vhd delete logic was executed
for managed disks vm which led to a nil pointer exception. This
would disrupt the deletion process for all resources and lead to
remnant resources in Azure. Now, storage accounts are not created
for managed disks, and all resources are properly deleted whether
managed disks were used or not.

drivers/azure/azure.go

@@ -419,8 +419,11 @@ func (d *Driver) Create() error {
 		d.ctx.PublicIPAddressID, d.ctx.SubnetID, d.ctx.NetworkSecurityGroupID, d.PrivateIPAddr); err != nil {
 		return err
 	}
-	if err := c.CreateStorageAccount(d.ctx, d.ResourceGroup, d.Location, storage.SkuName(d.StorageType)); err != nil {
-		return err
+	if !d.ManagedDisks {
+		// storage account is only necessary when using unmanaged disks
+		if err := c.CreateStorageAccount(d.ctx, d.ResourceGroup, d.Location, storage.SkuName(d.StorageType)); err != nil {
+			return err
+		}
 	}
 	if err := d.generateSSHKey(d.ctx); err != nil {
 		return err

drivers/azure/azureutil/azureutil.go

@@ -429,9 +429,16 @@ func (a AzureClient) DeleteVirtualMachineIfExists(resourceGroup, name string) er
 	}
 
 	// Remove disk
-	if vmRef.VirtualMachineProperties != nil {
-		vhdURL := to.String(vmRef.VirtualMachineProperties.StorageProfile.OsDisk.Vhd.URI)
-		return a.removeOSDiskBlob(resourceGroup, name, vhdURL)
+	if vmProperties := vmRef.VirtualMachineProperties; vmProperties != nil {
+		// TODO: remove unattached managed disk, requires azure sdk upgrade
+		if managedDisk := vmProperties.StorageProfile.OsDisk.ManagedDisk; managedDisk != nil {
+			diskName := fmt.Sprintf("%s-os-disk", name)
+			log.Infof("Disk [%s] in resource group [%s] must be removed manually.", diskName, resourceGroup)
+		}
+		// if vhd is not nil then disk is unmanaged and disk blob should be removed
+		if vhd := vmProperties.StorageProfile.OsDisk.Vhd; vhd != nil {
+			return a.removeOSDiskBlob(resourceGroup, name, to.String(vhd.URI))
+		}
 	}
 	return nil
 }
@@ -512,11 +519,7 @@ func (a AzureClient) CreateVirtualMachine(resourceGroup, name, location, size, a
 		return err
 	}
 
-	var (
-		osDiskBlobURL = osDiskStorageBlobURL(storageAccount, name)
-		sshKeyPath    = fmt.Sprintf("/home/%s/.ssh/authorized_keys", username)
-	)
-	log.Debugf("OS disk blob will be placed at: %s", osDiskBlobURL)
+	sshKeyPath := fmt.Sprintf("/home/%s/.ssh/authorized_keys", username)
 	log.Debugf("SSH key will be placed at: %s", sshKeyPath)
 
 	var osProfile = &compute.OSProfile{
@@ -564,7 +567,7 @@ func (a AzureClient) CreateVirtualMachine(resourceGroup, name, location, size, a
 						Sku:       to.StringPtr(img.sku),
 						Version:   to.StringPtr(img.version),
 					},
-					OsDisk: getOSDisk(name, osDiskBlobURL, isManaged, storageType, diskSize),
+					OsDisk: getOSDisk(name, storageAccount, isManaged, storageType, diskSize),
 				},
 			},
 		}, nil)
@@ -573,7 +576,7 @@ func (a AzureClient) CreateVirtualMachine(resourceGroup, name, location, size, a
 
 // GetOSDisk creates and returns pointer to a disk that is configured for either managed or unmanaged disks depending
 // on setting.
-func getOSDisk(name string, osDiskBlobURL string, isManaged bool, storageType string, diskSize int32) *compute.OSDisk {
+func getOSDisk(name string, account *storage.AccountProperties, isManaged bool, storageType string, diskSize int32) *compute.OSDisk {
 	var osdisk *compute.OSDisk
 	if isManaged {
 		osdisk = &compute.OSDisk{
@@ -586,6 +589,8 @@ func getOSDisk(name string, osDiskBlobURL string, isManaged bool, storageType st
 			DiskSizeGB: to.Int32Ptr(diskSize),
 		}
 	} else {
+		osDiskBlobURL := osDiskStorageBlobURL(account, name)
+		log.Debugf("OS disk blob will be placed at: %s", osDiskBlobURL)
 		osdisk = &compute.OSDisk{
 			Name:         to.StringPtr(fmt.Sprintf(fmtOSDiskResourceName, name)),
 			Caching:      compute.ReadWrite,
@@ -840,6 +845,10 @@ func checkResourceExistsFromError(err error) (bool, error) {
 // osDiskStorageBlobURL gives the full url of the VHD blob where the OS disk for
 // the given VM should be stored.
 func osDiskStorageBlobURL(account *storage.AccountProperties, vmName string) string {
+	if account == nil {
+		return ""
+	}
+
 	containerURL := osDiskStorageContainerURL(account, vmName) // has trailing slash
 	blobName := fmt.Sprintf(fmtOSDiskBlobName, vmName)
 	return containerURL + blobName