Azure - Managed Disks, how to create snapshot

Question

I have application which deploy VM with storage account and disks, I want to convert it to use managed disks - as this is the future of Azure storage. I am looking on the REST API - and I am missing two things: 1. how can i create a snapshot form existing managed disk, there is an API to create a snapshot but it is empty or from old unmanaged 2. can i choose the lun on which the disk is created?

Brando Zhang · Accepted Answer

how can i create a snapshot form existing managed disk, there is an API to create a snapshot but it is empty or from old unmanaged

According to your description, I have created a test demo to create a snapshot of an existing managed disk(OS disk), it works well. I create a Windows VM and use managed disk as the OS disk, then I create another managed disk and add it to the VM.

The result is like below: If you want to create a snapshot of an existing managed disk(It has the data), I suggest you could send request to below url.

Url: https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroup}/providers/Microsoft.Compute/snapshots/{snapshotName}?api-version={api-version}

Method: PUT

Parameter:
subscriptionId  The identifier of your subscription where the snapshot is being created.
resourceGroup   The name of the resource group that will contain the snapshot.
snapshotName    The name of the snapshot that is being created. The name can’t be changed after the snapshot is created. Supported characters for the name are a-z, A-Z, 0-9 and _. The max name length is 80 characters.
api-version The version of the API to use. The current version is 2016-04-30-preview.

Request content:
{
  "properties": {
    "creationData": {
      "createOption": "Copy",
      "sourceUri": "/subscriptions/{subscriptionId}/resourceGroups/{YourResourceGroup}/providers/Microsoft.Compute/disks/{YourManagedDiskName}"
    }
  },
  "location": "eastasia"
}

More details, you could refer to follow C# codes:

json.txt:

{
  "properties": {
    "creationData": {
      "createOption": "Copy",
      "sourceUri": "/subscriptions/xxxxxxxxxxxxxxxxxxxxxxxx/resourceGroups/BrandoSecondTest/providers/Microsoft.Compute/disks/BrandoTestVM"
    }
  },
  "location": "eastasia"
}

Code:

static void Main(string[] args)
        {
            string body = File.ReadAllText(@"D:\json.txt");
            // Display the file contents to the console. Variable text is a string.
            string tenantId = "xxxxxxxxxxxxxxxxxxxxxxxx";
            string clientId = "xxxxxxxxxxxxxxxxxxxxxxxx";
            string clientSecret = "xxxxxxxxxxxxxxxxxxxx";
            string authContextURL = "https://login.windows.net/" + tenantId;
            var authenticationContext = new AuthenticationContext(authContextURL);
            var credential = new ClientCredential(clientId, clientSecret);
            var result = authenticationContext.AcquireTokenAsync(resource: "https://management.azure.com/", clientCredential: credential).Result;
            if (result == null)
            {
               throw new InvalidOperationException("Failed to obtain the JWT token");
            }
            string token = result.AccessToken;
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("https://management.azure.com/subscriptions/xxxxxxxxxxxxxxxxxxxxxxxxx/resourceGroups/xxxxxxxxxxxxxxxx/providers/Microsoft.Compute/snapshots/BrandoTestVM_snapshot2?api-version=2016-04-30-preview");
            request.Method = "PUT";
            request.Headers["Authorization"] = "Bearer " + token;
            request.ContentType = "application/json";

            try
            {
                using (var streamWriter = new StreamWriter(request.GetRequestStream()))
                {
                    streamWriter.Write(body);
                    streamWriter.Flush();
                    streamWriter.Close();
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            //Get the response
           var httpResponse = (HttpWebResponse)request.GetResponse();
            using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
            {
                Console.WriteLine(streamReader.ReadToEnd());
            }

            Console.ReadLine();
        }

Result:

can i choose the lun on which the disk is created?

Do you mean you want to use azuredeploy to select the LUN of the disk?

If this is your opinion, I suggest you could refer to follow json example to know how to build the deploy content of the VM and select its LUN.

More details, you could refer to below deploymentTemplate Json (Partly):

"diskArray": [
    {
    "name": "datadisk1",
    "lun": 0,
    "vhd": {
    "uri": "[concat('http://', variables('storageAccountName'),'.blob.core.windows.net/vhds/', 'datadisk1.vhd')]"
    },
    "createOption": "Empty",
    "caching": "[variables('diskCaching')]",
    "diskSizeGB": "[variables('sizeOfDataDisksInGB')]"
    },
  ]

More details, you could refer to follow link: 201-vm-dynamic-data-disks-selection/azuredeploy.json

Azure - Managed Disks, how to create snapshot

Answers (2)

Provide the subscription Id of the subscription subscriptionId=88888-8888-888888-8888-8888888

Provide the name of your resource group

Provide the name of the snapshot that will be used to create Managed Disks(this was created in previous step)

Provide the name of the Managed Disk which will be created

Provide the size of the disks in GB. It should be greater than the VHD file size.

Set the context to the subscription Id where Managed Disk will be created

Get the snapshot Id

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