Implementing Network Policies for Azure Databricks (AI Secure Connectivity)

Question

Pulumi · Accepted Answer

To implement network policies for Azure Databricks that ensure secure connectivity, we will utilize Pulumi to programmatically define the infrastructure required. In the context of Azure, network policies typically revolve around Network Security Groups (NSGs), which are used to filter network traffic to and from Azure resources within an Azure Virtual Network (VNet).

Azure Databricks does not have direct support for NSGs within the Databricks workspace, but you can control access to the workspace at the networking level by deploying Azure Databricks in your own VNet. Once deployed in a VNet, you can apply NSGs to the subnets associated with the Databricks workspace to define inbound and outbound security rules.

Below is a Pulumi program written in Python that creates a VNet, a subnet with a Network Security Group associated with it, and then deploys an Azure Databricks workspace into this subnet, achieving secure connectivity through the defined network policies.

### Detailed Explanation and Pulumi Program

```python
import pulumi
from pulumi_azure_native import resources
from pulumi_azure_native import network
from pulumi_azure_native import databricks

# Define a resource group where all the resources will be created.
resource_group = resources.ResourceGroup('databricks-rg')

# Create a virtual network where we will deploy Azure Databricks.
vnet = network.VirtualNetwork(
    'databricks-vnet',
    resource_group_name=resource_group.name,
    address_space=network.AddressSpaceArgs(
        address_prefixes=['10.0.0.0/16']
    ),
    subnets=[network.SubnetArgs(
        name='databricks-subnet',
        address_prefix='10.0.1.0/24'
    )]
)

# Define a network security group that will contain security rules for our Databricks subnet.
nsg = network.NetworkSecurityGroup(
    'databricks-nsg',
    resource_group_name=resource_group.name,
    location=resource_group.location,
    security_rules=[network.SecurityRuleArgs(
        name='ALLOW-DATABRICKS',
        priority=100,
        direction='Inbound',
        access='Allow',
        protocol='Tcp',
        source_port_range='*',
        destination_port_range='*',
        source_address_prefix='*',
        destination_address_prefix='*',
        description='Allow all inbound traffic to Databricks',
    )]
)

# Associate the network security group with our subnet.
subnet_update = network.Subnet(
    'databricks-subnet-update',
    resource_group_name=resource_group.name,
    virtual_network_name=vnet.name,
    address_prefix='10.0.1.0/24',
    network_security_group=nsg,
    name='databricks-subnet'
)

# Create an Azure Databricks workspace and deploy it in the subnet.
databricks_workspace = databricks.Workspace(
    'databricks-workspace',
    resource_group_name=resource_group.name,
    location=resource_group.location,
    sku='standard',
    parameters=databricks.WorkspaceCustomParametersArgs(
        custom_virtual_network_id=vnet.id,
        custom_public_subnet_name=subnet_update.name,
        custom_private_subnet_name=subnet_update.name
    )
)

pulumi.export('databricks_workspace_url', databricks_workspace.workspace_url)
```

In this program, we're defining the following resources:

1. **Resource Group**: The container that holds related resources for an Azure solution.
2. **Virtual Network (VNet)**: Provides network isolation for your Databricks workspace.
3. **Subnet**: A subdivision within a VNet where you can deploy your resources. Azure Databricks will be deployed within this subnet.
4. **Network Security Group (NSG)**: Contains a list of security rules allowing or denying network traffic to resources connected to VNets. In this case, we're allowing all inbound traffic.
5. **NSG Association**: We associate the NSG with the subnet meant for Databricks.
6. **Azure Databricks Workspace**: This resource represents an Azure Databricks workspace where data analytics can take place. It's being deployed in the previously created subnet.

Please note that the `network.SecurityRuleArgs` specify that all inbound traffic is allowed. Depending on your particular security requirements, you likely want to limit the source IP ranges and the destination ports to what's required by your Databricks workloads.

The final `pulumi.export` statement makes the URL of the created Databricks workspace available as an output once the Pulumi program is applied. This allows you to easily access the Databricks workspace and verify connectivity.

Remember to adjust security rules according to the least privilege principle, and consider your organization's security policies when defining them.