Map a custom domain to an Azure Blob Storage endpoint

  • Article

You can map a custom domain to a blob service endpoint or a static website endpoint.

Note

This mapping works only for subdomains (for example: www.contoso.com).

Map a custom domain with only HTTP enabled

This approach is easier, but enables only HTTP access.

Map a custom domain

Important

Your custom domain will be briefly unavailable to users while you complete the configuration. If your domain currently supports an application with a service-level agreement (SLA) that requires zero downtime, then follow the steps in the Map a custom domain with zero downtime section of this article to ensure that users can access your domain while the DNS mapping takes place.

If you are unconcerned that the domain is briefly unavailable to your users, follow these steps.

✔️ Step 1: Get the host name of your storage endpoint.

✔️ Step 2: Create a canonical name (CNAME) record with your domain provider.

✔️ Step 3: Register the custom domain with Azure.

✔️ Step 4: Test your custom domain.

Step 1: Get the host name of your storage endpoint

The host name is the storage endpoint URL without the protocol identifier and the trailing slash.

  1. In the Azure portal, go to your storage account.

  2. In the menu pane, under Settings, select Endpoints.

  3. Copy the value of the Blob service endpoint or the Static website endpoint to a text file.

    Note

    The Data Lake storage endpoint is not supported (For example: https://mystorageaccount.dfs.core.chinacloudapi.cn/).

  4. Remove the protocol identifier (For example: HTTPS) and the trailing slash from that string. The following table contains examples.

    Type of endpoint endpoint host name
    blob service https://mystorageaccount.blob.core.chinacloudapi.cn/ mystorageaccount.blob.core.chinacloudapi.cn
    static website https://mystorageaccount.z4.web.core.chinacloudapi.cn/ mystorageaccount.z4.web.core.chinacloudapi.cn

    Set this value aside for later.

Step 2: Create a canonical name (CNAME) record with your domain provider

Create a CNAME record to point to your host name. A CNAME record is a type of Domain Name System (DNS) record that maps a source domain name to a destination domain name.

  1. Sign in to your domain registrar's website, and then go to the page for managing DNS setting.

    You might find the page in a section named Domain Name, DNS, or Name Server Management.

  2. Find the section for managing CNAME records.

    You might have to go to an advanced settings page and look for CNAME, Alias, or Subdomains.

  3. Create a CNAME record. As part of that record, provide the following items:

    • The subdomain alias such as www or photos. The subdomain is required, root domains are not supported.

    • The host name that you obtained in the Get the host name of your storage endpoint section earlier in this article.

Step 3: Register your custom domain with Azure

  1. In the Azure portal, go to your storage account.

  2. In the menu pane, under Security + networking, select Networking.

  3. In the Networking page, choose the Custom domain tab.

    Note

    This option does not appear in accounts that have the hierarchical namespace feature enabled. For those accounts, use either PowerShell or the Azure CLI to complete this step.

  4. In the Domain name text box, enter the name of your custom domain, including the subdomain.

    For example, if your domain is contoso.com and your subdomain alias is www, enter www.contoso.com. If your subdomain is photos, enter photos.contoso.com.

  5. To register the custom domain, choose the Save button.

    After the CNAME record has propagated through the Domain Name Servers (DNS), and if your users have the appropriate permissions, they can view blob data by using the custom domain.

Step 4: Test your custom domain

To confirm that your custom domain is mapped to your blob service endpoint, create a blob in a public container within your storage account. Then, in a web browser, access the blob by using a URI in the following format: http://<subdomain.customdomain>/<mycontainer>/<myblob>

For example, to access a web form in the myforms container in the photos.contoso.com custom subdomain, you might use the following URI: http://photos.contoso.com/myforms/applicationform.htm

Map a custom domain with zero downtime

Note

If you are unconcerned that the domain is briefly unavailable to your users, then consider using the steps in the Map a custom domain section of this article. It's a simpler approach with fewer steps.

If your domain currently supports an application with a service-level agreement (SLA) that requires zero downtime, then follow these steps to ensure that users can access your domain while the DNS mapping takes place.

✔️ Step 1: Get the host name of your storage endpoint.

✔️ Step 2: Create an intermediary canonical name (CNAME) record with your domain provider.

✔️ Step 3: Pre-register the custom domain with Azure.

✔️ Step 4: Create a CNAME record with your domain provider.

✔️ Step 5: Test your custom domain.

Step 1: Get the host name of your storage endpoint

The host name is the storage endpoint URL without the protocol identifier and the trailing slash.

  1. In the Azure portal, go to your storage account.

  2. In the menu pane, under Settings, select Endpoints.

  3. Copy the value of the Blob service endpoint or the Static website endpoint to a text file.

  4. Remove the protocol identifier (For example: HTTPS) and the trailing slash from that string. The following table contains examples.

    Type of endpoint endpoint host name
    blob service https://mystorageaccount.blob.core.chinacloudapi.cn/ mystorageaccount.blob.core.chinacloudapi.cn
    static website https://mystorageaccount.z4.web.core.chinacloudapi.cn/ mystorageaccount.z4.web.core.chinacloudapi.cn

    Set this value aside for later.

Step 2: Create an intermediary canonical name (CNAME) record with your domain provider

Create a temporary CNAME record to point to your host name. A CNAME record is a type of DNS record that maps a source domain name to a destination domain name.

  1. Sign in to your domain registrar's website, and then go to the page for managing DNS setting.

    You might find the page in a section named Domain Name, DNS, or Name Server Management.

  2. Find the section for managing CNAME records.

    You might have to go to an advanced settings page and look for CNAME, Alias, or Subdomains.

  3. Create a CNAME record. As part of that record, provide the following items:

    • The subdomain alias such as www or photos. The subdomain is required, root domains are not supported.

      Add the asverify subdomain to the alias. For example: asverify.www or asverify.photos.

    • The host name that you obtained in the Get the host name of your storage endpoint section earlier in this article.

      Add the subdomain asverify to the host name. For example: asverify.mystorageaccount.blob.core.chinacloudapi.cn.

Step 3: Pre-register your custom domain with Azure

When you pre-register your custom domain with Azure, you permit Azure to recognize your custom domain without having to modify the DNS record for the domain. That way, when you do modify the DNS record for the domain, it will be mapped to the blob endpoint with no downtime.

  1. In the Azure portal, go to your storage account.

  2. In the menu pane, under Security + networking, select Networking.

  3. In the Networking page, choose the Custom domain tab.

    Note

    This option does not appear in accounts that have the hierarchical namespace feature enabled. For those accounts, use either PowerShell or the Azure CLI to complete this step.

  4. In the Domain name text box, enter the name of your custom domain, including the subdomain.

    For example, if your domain is contoso.com and your subdomain alias is www, enter www.contoso.com. If your subdomain is photos, enter photos.contoso.com.

  5. Select the Use indirect CNAME validation check box.

  6. To register the custom domain, choose the Save button.

    If the registration is successful, the portal notifies you that your storage account was successfully updated. Your custom domain has been verified by Azure, but traffic to your domain is not yet being routed to your storage account until you create a CNAME record with your domain provider. You'll do that in the next section.

Step 4: Create a CNAME record with your domain provider

Create a temporary CNAME record to point to your host name.

  1. Sign in to your domain registrar's website, and then go to the page for managing DNS setting.

    You might find the page in a section named Domain Name, DNS, or Name Server Management.

  2. Find the section for managing CNAME records.

    You might have to go to an advanced settings page and look for CNAME, Alias, or Subdomains.

  3. Create a CNAME record. As part of that record, provide the following items:

    • The subdomain alias such as www or photos. The subdomain is required, root domains are not supported.

    • The host name that you obtained in the Get the host name of your storage endpoint section earlier in this article.

Step 5: Test your custom domain

To confirm that your custom domain is mapped to your blob service endpoint, create a blob in a public container within your storage account. Then, in a web browser, access the blob by using a URI in the following format: http://<subdomain.customdomain>/<mycontainer>/<myblob>

For example, to access a web form in the myforms container in the photos.contoso.com custom subdomain, you might use the following URI: http://photos.contoso.com/myforms/applicationform.htm

Remove a custom domain mapping

To remove a custom domain mapping, deregister the custom domain. Use one of the following procedures.

  1. In the Azure portal, go to your storage account.

  2. In the menu pane, under Security + networking, select Networking.

  3. In the Networking page, choose the Custom domain tab.

  4. Clear the contents of the text box that contains your custom domain name.

  5. Select the Save button.

After the custom domain has been removed successfully, you will see a portal notification that your storage account was successfully updated.

Feature support

Support for this feature might be impacted by enabling Data Lake Storage Gen2, Network File System (NFS) 3.0 protocol, or the SSH File Transfer Protocol (SFTP). If you've enabled any of these capabilities, see Blob Storage feature support in Azure Storage accounts to assess support for this feature.

Next steps