🏗️ Understanding Azure Databricks Architecture – Control Plane vs Data Plane

When working with Azure Databricks, it’s crucial to understand the underlying architecture to make the most of its performance, security, and scalability. Azure Databricks architecture is based on a split-plane model, offering a clean separation of concerns through a Control Plane and Data Plane.

In this blog, we’ll demystify the architecture of Azure Databricks using a visual walkthrough.

🚀 Overview: What Is Azure Databricks?

Azure Databricks is a first-party Microsoft Azure service that provides:

• A managed Apache Spark environment
• Optimized data engineering and ML workloads
• Integration with Azure services like ADLS, ADF, and Power BI

🔧 Azure Databricks Architecture Breakdown

The architecture can be divided into two main components:

🟥 1. Control Plane (Managed by Databricks)

This is hosted in the Databricks subscription, outside of your Azure environment.

💼 Key Components:

• Databricks UX: The web-based interface where users interact with notebooks, jobs, clusters, etc.
• Databricks Cluster Manager: Manages the lifecycle of compute clusters (create, start, terminate).
• DBFS (Databricks File System): An abstraction layer for object storage, allowing easy access to data files.
• User Authentication: Managed via Azure Active Directory (AAD) to ensure secure and unified login.

📍 This plane is responsible for orchestration, control, and user interaction.

🟩 2. Data Plane (Hosted in Your Azure Subscription)

This is where your data resides and your computations actually run. It ensures security and data compliance by keeping all operations within your Azure boundary.

💡 Components in the Data Plane:

• Virtual Network (VNet): Optional but recommended for networking and security controls.
• VMs (Virtual Machines): Spark workloads run here – these VMs are dynamically created and scaled.
• Azure Blob Storage / ADLS: For storing raw, processed, and curated datasets.
• Databricks Workspace: Deployed within your subscription and integrated with networking and storage services.

🔐 The data plane executes your Spark code, processes your data, and manages storage—all within your control.

🔐 Azure Active Directory (Azure AD) Integration

• Azure AD is used for identity and access management (IAM).
• Users authenticate through AAD before accessing Databricks.
• Ensures secure, role-based access to workspaces and resources.

🔄 Azure Resource Manager (ARM)

• ARM acts as a bridge between Azure services and Databricks.
• Used to deploy, update, and manage Databricks workspaces and components via templates or the Azure portal.

📊 Visual Recap of Architecture

Here’s a simplified version of the diagram you shared:

+-------------------+          +-----------------------------+
|   Azure AD        |          |   Azure Resource Manager    |
+-------------------+          +-----------------------------+
          ↓                            ↓
+-------------------------------------------+
|       Control Plane (Databricks)          |
|   - UX Interface                          |
|   - Cluster Manager                       |
|   - DBFS                                  |
+-------------------------------------------+
                  ↓
+-------------------------------------------+
|       Data Plane (Customer Subscription)  |
|   - Virtual Network (VNet) + NSG          |
|   - Virtual Machines (VMs)                |
|   - Azure Blob Storage / ADLS             |
|   - Databricks Workspace                  |
+-------------------------------------------+

✅ Benefits of the Two-Plane Architecture

🎯 When Should You Care?

• You’re working in a regulated environment (healthcare, finance, etc.) and need data locality.
• You want to control networking, firewalls, and VNet rules.
• You’re planning a production-grade ETL or ML pipeline and need fine-grained resource control.

🧠 Final Thoughts

Understanding the Azure Databricks architecture is key to building secure, scalable, and high-performance data solutions. With the separation of Control Plane and Data Plane, you get the best of both worlds—ease of use and enterprise-level security.