> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sync.cdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Azure Blob Storage

You can use the Azure Blob Storage connector from the CData Sync application to move data
from any supported source to the Azure Blob Storage destination. To do so, you need to add
the connector, authenticate to the connector, and complete your connection.

## LakeBridge Connector for Delta Parquet and Apache Iceberg

The **Delta Parquet** and **Apache Iceberg** file formats require the LakeBridge connector. Before you configure the Azure Blob Storage destination with either of these file formats, install the LakeBridge connector in Sync.

When Sync starts, it launches the LakeBridge server as a background service on the local machine. When a Delta Parquet or Apache Iceberg job runs, the LakeBridge server starts a dedicated Spark JVM for that job and shuts it down after the job finishes. This isolates each job's memory and allows multiple jobs to run in parallel with independent Spark sessions.

By default, up to three LakeBridge jobs can run concurrently. You can change this limit with the `MaxConcurrentLakeBridgeJobs` setting in **System Settings** > **Advanced** > **Other Settings**. For details, see [Memory Management](https://docs.sync.cdata.com/26.4/en/getting-started/installation-and-configuration/memory-management.md).

To install the LakeBridge connector:

<ol>
  <li>In Sync, navigate to **Connections**.</li>

  <li>
    Select **... > Update Connector** at the end of the Azure Blob Storage row.

    > [!NOTE]
    >
    > Before you complete this step, you must add the Azure Blob Storage connector. For instructions, see "Add the Azure Blob Storage Connector" below.
  </li>

  <li>Select **Add New Version** in the **Update Connector** dialog.</li>
  <li>Upload the `lakebridge.zip` file that is provided by the CData Sync support team.</li>
  <li>Click **Update**.</li>
</ol>

When you install a newer version of the LakeBridge connector, the LakeBridge server stops and restarts automatically on the next job run. A Sync restart is not required.

## Microsoft Windows Prerequisites for Delta Parquet

Before you configure the Azure Blob Storage destination with the **Delta Parquet** file format in the Microsoft Windows operating system (OS), make sure that your environment meets the requirements explained below. These prerequisites ensure that Sync can interact correctly with Delta Lake by locating the required Hadoop binaries under Windows.

Configure your Windows OS, as follows:

<ul><li>Download Hadoop binaries (recommended version: 2.8.1 or later).</li>
<li>Ensure that `HADOOP_HOME` environment variable to the Hadoop installation directory.</li>
<li>Ensure that `%HADOOP_HOME%\bin` is included in your `PATH` system variable (specifically, `%HADOOP_HOME%\bin\winutils.exe` must be accessible).</li></ul>

This configuration is necessary because Delta Lake (on Spark) uses Hadoop's file system APIs to access local storage, the Hadoop Distributed File System (HDFS), and cloud object stores like Azure Blob Storage. Under Windows, Spark must be able to locate the Hadoop binaries (including winutils.exe and other native libraries) to function correctly. Without this configuration, operations such as writing Delta tables, managing checkpoints, or accessing cloud storage can fail with permission or file-system errors.

## Supported File Formats

When Sync writes data to Azure Blob Storage, you can choose the file format for the exported data. The following file formats are supported for the Azure Blob Storage destination:

* (Default) **Delta Parquet:** A format that uses a Delta Lake storage layer on top of the Parquet file format that is used by Sync to support delta processing. *Delta processing* is a method where, after your initial job run, only new or modified files are written or read in subsequent runs, which can reduce job times and resource use.

  **Limitations:**

  * **Naming restrictions:** Table and column names cannot include special characters or reserved SQL and Delta Lake keywords. Examples of special characters include spaces, commas, semicolons, braces, parentheses, equal signs, and the newline (`\n`) and tab (`\t`) characters.
  * **Primary keys:** Primary key constraints are not supported. Sync uses the source primary keys for incremental replication.
  * **Data types:** Unlike traditional databases, Delta Lake does not support column-size definitions (for example, `VARCHAR(100)`). It supports only a fixed set of data types and allows type widening when necessary.
  * **Schema changes:** The ALTER TABLE command supports only adding new columns. Changing the data type of an existing column (for example, from INT to VARCHAR) is not supported.
  * **Delete operations:** In standard jobs, both hard and soft deletions are supported. In CDC and enhanced CDC jobs, only soft deletions are supported.
* **Apache Iceberg:** A high-performance table format that supports atomicity, consistency, isolation, and durability (ACID) transactions and schema evolution.
* **CSV:** Plain text comma-separated values.
* **Avro:** A row-based binary format that supports schema evolution.
* **Parquet:** A columnar storage format that is optimized for analytics.

## Add the Azure Blob Storage Connector

To enable Sync to use data from Azure Blob Storage, you first must add the
connector, as follows:

<ol>
  <li>Open the **Connections** page of the Sync dashboard.</li>
  <li>Click **Add Connection** to open the **Select Connectors** page.</li>
  <li>Click the **Destinations** tab and locate
  the **Azure Blob Storage** row.</li>

  <li>
    Click the **Configure Connection** icon at the end of that row to open
    the **New Connection** page. This action opens the
    **Add Connection** dialog.

    **Note:** If the **Configure Connection** icon is not
    available, click the **Download Connector** icon to install
    the Azure Blob Storage connector.
  </li>

  <li>Enter a name for your connection in the **Add Connection** dialog.</li>
  <li>Click **Add** to open the **Settings** tab for your connector.</li>
</ol>

For more information about installing new connectors, see
[Connections](https://docs.sync.cdata.com/26.4/en/connections/connections.md).

## Authenticate to Azure Blob Storage

After you add the connector, you need to set the required properties.

* **File Format:** Select the file format that you want to use: **Delta Parquet** (default), **Apache Iceberg**, **CSV** , **Avro**, or **Parquet**.
* **URI:** Enter the path of your container and the name of the blob (for example, `azureblob://MyContainer/MyBlob`).
* **Azure Storage Account:** Specify the storage account that should be used in Azure Blob Storage.

CData Sync supports authenticating to Azure Blob Storage in several ways. Select your authentication method below to proceed to the relevant section that contains the authentication details.

* [**Azure Active Directory**](#azure-active-directory)
* [**Azure Managed Service Identity**](#azure-managed-service-identity)
* [**Azure Service Principal**](#azure-service-principal)
* [**Azure Service Principal Certificate**](#azure-service-principal-certificate)
* [**Azure Access Key**](#azure-access-key) (default)
* [**Azure Storage SAS**](#azure-shared-access-signature)

**Note:** The full list of authentication methods above are for all file formats except **Delta Parquet**. That format uses only the **Access Key** method.

### Azure Active Directory

To connect with an Azure Active Directory (AD) user account, specify the following properties:

* **Auth Scheme:** select **AzureAD**.
* **Use Lake Formation:** Select whether you want the AWS Lake Formation service to retrieve temporary credentials. These temporary credentials enforce access policies against the user based on the configured IAM role. You can use this service when you authenticate through AzureAD, Okta, ADFS, and PingFederate, while providing a Security Assertion Markup Language (SAML) assertion. By default, the **Enable** checkbox is not selected.

### Azure Managed Service Identity

To leverage Azure Managed Service Identity (MSI) when CData Sync is running on an Azure
virtual machine, select **Azure MSI** for **Auth Scheme**. No
additional properties are required.

### Azure Service Principal

To connect with an Azure service principal and client secret, set the following properties:

<ul><li>**Auth Scheme:** Select **AzureServicePrincipal**.</li>
<li>**Azure Tenant:** Enter the Microsoft Online tenant to which you want to connect.</li>
<li>**OAuth Client Id:** Enter the client Id that you were assigned when you registered your application with an OAuth authorization server.</li>
<li>**OAuth Client Secret:** Enter the client secret that you were assigned when you registered your application with an OAuth authorization server.</li>
<li>(Optional) **Scope:** Specify the scope of your access to the application.</li>
<li>(Optional) **OAuth Authorization URL:** Enter the OAuth authorization URL for the OAuth service.</li>
<li>(Optional) **OAuth Access Token URL:** Enter the URL from which to retrieve the access token.</li>
<li>(Optional) **OAuth Refresh Token URL:** Enter the URL from which to refresh the OAuth token.</li></ul>

To obtain the OAuth client Id and client secret for your application:

<ol><li>Log in to the [Azure portal](https://portal.azure.com).</li>
<li>In the left navigation pane, select **All services**. Then, search for and select **App registrations**.</li>
<li>Click **New registrations**.</li>
<li>Enter an application name and select **Any Azure AD Directory - Multi Tenant**.</li>
<li>After you create the application, copy the application (client) Id value that is displayed in the **Overview** section. Use this value as the OAuth client Id.</li>
<li>Navigate to the **Certificates & Secrets** section and select **New Client Secret** for the application.</li>
<li>Specify the duration and save the client secret. After you save it, the key value is displayed.</li>
<li>Copy this value because it is displayed only once. You will use this value as the OAuth client secret.</li>
<li>On the **Authentication** tab, make sure to select **Access tokens (used for implicit flows)**.</li></ol>

### Azure Service Principal Certificate

To connect with an Azure service principal and client certificate, set the following properties:

<ul><li>**Auth Scheme:** Select **AzureServicePrincipalCert**.</li>
<li>**Azure Tenant:** Enter the Microsoft Online tenant to which you want to connect.</li>
<li>**OAuth JWT Cert:** Enter your Java web tokens (JWT) certificate store.</li>
<li>**OAuth JWT Cert Type:** Enter the type of key store that contains your JWT Certificate. The default type is **PEMKEY\_BLOB**.</li>
<li>**OAuth Client Id:** Enter the client Id that you were assigned when you registered your application with an OAuth authorization server.</li>
<li>(Optional) **Scope:** Specify the scope of your access to the application.</li>
<li>(Optional) **OAuth Authorization URL:** Enter the OAuth authorization URL for the OAuth service.</li>
<li>(Optional) **OAuth Access Token URL:** Enter the URL from which to retrieve the access token.</li>
<li>(Optional) **OAuth Refresh Token URL:** Enter the URL from which to refresh the OAuth token.</li>
<li>(Optional) **OAuth JWT Cert Password:** Enter the password for your OAuth JWT certificate.</li>
<li>(Optional) **OAuth JWT Cert Subject:** Enter the subject of your OAuth JWT certificate.</li></ul>

To obtain the OAuth certificate for your application:

<ol><li>Log in to the [Azure portal](https://portal.azure.com).</li>
<li>In the left navigation pane, select **All services**. Then, search for and select **App registrations**.</li>
<li>Click **New registrations**.</li>
<li>Enter an application name and select **Any Azure AD Directory - Multi Tenant**.</li>
<li>After you create the application, copy the application (client) Id value that is displayed in the **Overview** section. Use this value as the OAuth client Id.</li>
<li>Navigate to the **Certificates & Secrets** section and select **Upload certificate**. Then, select the certificate to upload from your local machine.</li>
<li>Specify the duration and save the client secret. After you save it, the key value is displayed.</li>
<li>Copy this value because it is displayed only once. You will use this value as the OAuth client secret.</li>
<li>On the **Authentication** tab, make sure to select **Access tokens (used for implicit flows)**.</li></ol>

### Azure Access Key

To connect with an Azure access key, set the following properties:

<ul><li>**Auth Scheme:** Select **Access Key**.</li>
<li>**Azure Access Key:** Enter the access key that is associated with your storage account.</li></ul>

To retrieve your access key:

<ol><li>Sign in to the [Azure portal](https://portal.azure.com/) with the credentials for your root account.</li>
<li>Click **Storage accounts** and select the storage account that you want to use.</li>
<li>Under **Settings**, click **Access keys**. Your storage account name and key are displayed on that page.</li></ol>

### Azure Shared Access Signature

To connect with an Azure shared access signature, set the following properties:

<ul><li>**Auth Scheme:** Select **AzureStorageSAS**.</li>
<li>**Azure Shared Access Signature:** Enter the shared access signature that is associated with the storage account.</li></ul>

To create an Azure shared access signature:

<ol><li>Sign in to the [Azure portal](https://portal.azure.com) with the credentials for your root account.</li>
<li>Click **Storage accounts** and select the storage account you want to use.</li>
<li>Under **Settings**, click **Shared Access Signature**.</li>
<li>Set the permissions and a date when the token will expire.</li>
<li>Click **Generate SAS** and copy the token that is generated.</li></ol>

## Complete Your Connection

To complete your connection:

1. Specify the following properties:

   **For the Delta Parquet, Apache Iceberg, and CSV file formats:**

   * **FMT:** Enter the format that you want to use to parse all text files. The default format is **CsvDelimited**.
   * **Aggregate Files:** Select whether you want to aggregate all the files that are located in the URI directory and that have the same schema into a single table named AggregatedFiles. By default, the **Enable** checkbox is not selected.
   * **Include Column Headers:** Select whether you want to obtain column headers from the first lines of the specified files. By default, the **Enable** checkbox is already selected.

   **For the Avro and Parquet file formats:**

   * **Data Model:** Select the data model that you want to use to parse documents for your format and to generate the database metadata. The default data model is **Document**.
   * **Aggregate Files:** Select whether you want to aggregate all the files that are located in the URI directory and that have the same schema into a single table named AggregatedFiles. By default, the **Enable** checkbox is not selected.

<ol start="2"><li>Define advanced connection settings on the **Advanced** tab. (In most cases, though, you should not need these settings.)</li>
<li>If you authenticate with AzureAD, click **Connect to Azure Blob Storage** to connect to your Azure Blob Storage account.</li>
<li>Click **Create & Test** to create your connection.</li></ol>


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