Configuring Azure storage

In some situations, it may be beneficial to store files of an on‑premise website on a Microsoft Azure Blob Storage account rather than on a local disk.

  • For example, if your server has a limited storage capacity and you need to save large amounts of file data. Using Microsoft Azure may be more convenient than upgrading your server, especially if the increased requirements are only temporary.
  • The same applies when running Kentico in Azure Web Apps, where use of blob storage is optional (unlike with Cloud Services).

Mapping media files or the file system or storage accounts enforcing HTTPS connections

Storage accounts can be configured to communicate exclusively over HTTPS via the Security transfer required setting available in the Azure portal. In such cases, additional configuration of the environment is required. See Mapping files to storage accounts enforcing HTTPS connections for details.

File name case

Unlike standard Windows file systems, the Microsoft Azure Blob storage is case-sensitive. To ensure consistent behavior, Kentico automatically converts all file and folder names to lower case when processing files on Azure storage.

Mapping files to Azure storage

To map media library folders to Azure storage, use the API and the built-in Azure storage provider:

  1. Add the following keys to the appSettings section of your project’s web.config file. Specify the storage account name and primary access key:

     <add key="CMSAzureAccountName" value="StorageAccountName" />
     <add key="CMSAzureSharedKey" value="PrimaryAccessKey" />

    To locate the values of these keys on Microsoft Azure:

    1. Open the Azure Management Portal in a browser and sign in.
    2. Open Storage accounts.
    3. Select your storage.
    4. Switch to the Access keys tab.
      • Use the Storage account name and one of the provided access key values.
  2. If you are using the MVC development model, configure the same keys in the web.config of your MVC live site application.

  3. Open the Kentico solution in Visual Studio (using the WebSite.sln or WebApp.sln file).

  4. Create a custom module class. Add the class into a custom Class Library project within the solution.

    • For basic execution of initialization code, you only need to register a “code-only” module through the API. You do NOT need to create a new module within the Modules application in the Kentico administration interface.
  5. Override the module’s OnInit method and perform the following:

    • Create a new instance of the Azure storage provider.
    • (Optional) Specify the target container using the CustomRootPath property of the provider.
    • (Optional) You can specify whether you want the container to be publicly accessible using the PublicExternalFolderObject property of the provider. True means the container is publicly accessible.
    • Map a directory to the provider. This is the directory that you want to store in the container.

using CMS;
using CMS.Base;
using CMS.DataEngine;
using CMS.IO;

// Registers the custom module into the system
[assembly: RegisterModule(typeof(CustomInitializationModule))]

public class CustomInitializationModule : Module
    // Module class constructor, the system registers the module under the name "CustomInit"
    public CustomInitializationModule()
        : base("CustomInit")

    // Contains initialization code that is executed when the application starts
    protected override void OnInit()

        // Creates a new StorageProvider instance for Azure
        var mediaProvider = StorageProvider.CreateAzureStorageProvider();

        // Specifies the target container
        mediaProvider.CustomRootPath = "mymediacontainer";

        // Makes the container publicly accessible
        mediaProvider.PublicExternalFolderObject = true;

        // Maps the local media library directory to the provider
        StorageHelper.MapStoragePath("~/MySite/Media/", mediaProvider);

  1. Save the file. If your project is installed in the web application format, rebuild the solution.
  2. If you are utilizing the MVC development model, you also need to deploy the assembly containing the custom storage provider code to the separate MVC application (in addition to the Kentico administration project).

The system now stores files from the ~/MySite/Media/ folder in the mymediacontainer on the Azure storage. See the Media library notes section on this page for additional information about media libraries when using Azure storage.

Mapping media folders on instances with multiple sites

By default, each site has its own separate media folder in the project’s file system: ~/<site code name>/media

To map all media folders to Azure storage on Kentico instances with multiple sites, we recommend using a shared root folder for media libraries:

  1. Open the Settings application in Kentico.
  2. Navigate to the Content -> Media settings category.
  3. Set the Media libraries folder to a custom folder (globally), for example: ~/SharedMedia
  4. Enable the Use site-specific subfolders for custom media libraries folder setting to ensure that individual library folders are separated by site.
  5. Click Save.
  6. Move any existing media library files to the new location.

You can then map the shared media folder to your Azure storage (using the API described above).

If you wish to use the default media folder locations, you need to map each site’s media folder in the code – for each site, create and configure a separate StorageProvider instance and call the StorageHelper.MapStoragePath method for the corresponding media folder.

Using Azure storage for multiple projects

We do not recommend using a single shared storage for multiple projects (for example production and testing instances), because the projects would overwrite each others’ files.

However, you can use the mediaProvider.CustomRootPath property (as described on this page) to map each project to a different container. This way, each project has its own section of the Azure storage and overwriting of files does not occur.

Mapping files to storage accounts enforcing HTTPS connections

Some external storage accounts may enforce HTTPS communication via the Security transfer required setting configurable in the Azure portal. When mapping the file system or media library files to such accounts, you must include the CMSAzureBlobEndPoint configuration key in the application’s web.config file. The key’s value needs to contain the full endpoint URL of the external storage account and explicitly use the https protocol:

    <add key="CMSAzureBlobEndPoint" value="" />

Media library notes

Using the Azure Blob storage as an external storage for your project has some specific effects on media libraries.

Storing too many files in one media library folder

Note that storing a large number of media files in a single folder can significantly affect the performance of user interface when editing files in the Media library application. The performance of the website, however, is not affected. See Media library limitations when storing files in an external storage for details.

If all following conditions are true:

  • you use the Azure Blob storage as an external storage
  • and you set the CMSAzurePublicContainer key to true
  • and you want to use content staging

then use Permanent links when linking to media files in media libraries.

The reason is that when using the CMSAzurePublicContainer key, direct file links contain the name of the storage in the URL. These links are not updated when staging files to another server, which is typically connected to a different storage. As a result, staged links incorrectly target files from the source server’s storage, or may become broken if the files are not exactly mirrored on the staging servers. Permanent links do not contain the name of the storage, and automatically target the correct storage for each server.

Optional web.config settings for Azure storage



Sample value


The system uses the specified folder to store temporary files on a local disk, for example when transferring large files to or from the storage account.

<add key="CMSAzureTempPath" value="C:\AzureTemp" />


Specifies a folder on a local disk where files requested from the storage account are cached. This helps minimize the amount of blob storage operations, which saves time and resources.

<add key="CMSAzureCachePath" value="C:\AzureCache" />


Sets the endpoint used for the connection to the blob service of the specified storage account. If you wish to use the default endpoint, remove the setting completely from the appropriate files.

<add key="CMSAzureBlobEndPoint" value="" />


Indicates if the blob container used to store the application’s file system is public. If true, it will be possible to access files directly through the URL of the appropriate blob service, for example:


When you set this key to true, please see the Media library notes section.

<add key="CMSAzurePublicContainer" value="true" />


URL of the HTTP endpoint of a Azure Blob storage CDN.

Note: If you set the CMSAzureCDNEndpoint key, you also need to set the blob storage container to public - <add key=“CMSAzurePublicContainer” value=“true” />.

<add key="CMSAzureCDNEndpoint" value="" />


Specifies the timeout interval in minutes for importing files from Azure Blob storage into Kentico.

The default value is 1.5 minutes. Increase the interval if you encounter problems when importing large (about 2GB) files.

<add key="CMSDownloadBlobTimeout" value="50" />