[ISSUE] Issue With Provider `databricks` Utilizing Github-oidc Against AWS Resource

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In this comprehensive article, we delve into a common issue encountered when using the Databricks provider with GitHub OIDC for authentication against AWS resources. The focus is on providing a detailed analysis of the problem, troubleshooting steps, and solutions. This article is designed to help you understand the intricacies of setting up and using GitHub OIDC with Databricks, ensuring a smooth and secure authentication process.

Background

When automating infrastructure deployments with Terraform, integrating Databricks with GitHub OIDC offers a secure and efficient authentication mechanism. However, misconfigurations or unsupported features can lead to authentication failures. This article addresses a specific scenario where users encounter the error message “databricks OAuth is not supported for this host” despite following the official Databricks documentation. Understanding the root cause and implementing the correct configurations are crucial for successful deployments.

Problem Statement

The primary issue arises when attempting to authenticate the Databricks provider using GitHub OIDC against AWS resources. The error message “databricks OAuth is not supported for this host” indicates a potential misconfiguration or an unsupported authentication method for the specified Databricks host. This problem typically occurs after setting up the databrickscfg file with the necessary credentials and attempting to run Terraform commands such as terraform plan. To effectively troubleshoot this, it’s essential to examine the configuration files, provider versions, and the authentication flow.

Configuration Details

To provide a clear understanding of the issue, let's examine the configuration files involved. These files dictate how Terraform interacts with the Databricks provider and authenticates against the Databricks workspace.

Terraform Configuration

The Terraform configuration file (main.tf) specifies the required provider versions and the Databricks provider settings. Here’s an example of a typical configuration:

terraform {
  required_version = ">= 1.10"
  required_providers {
    databricks = {
      source  = "databricks/databricks"
      version = "1.84.0"
    }
  }
}

provider "databricks" {
profile = "dev"
}


data "databricks_spark_version" "latest_lts" {
long_term_support = true
}

This configuration block defines the required Terraform version and the Databricks provider. The provider block specifies the profile to use for authentication, which in this case is “dev”. The data block fetches the latest long-term support (LTS) version of Spark, which requires successful authentication with the Databricks workspace.

Databricks Configuration File

The Databricks configuration file (databricks/.databrickscfg.ci) stores the authentication details, including the host URL, client ID, and authentication type. Here’s an example:

[dev]
host      = https://foobar-dev.cloud.databricks.com
client_id = xxxxxx-xxxx-xxxx-xxxx-xxxxxxxxx
auth_type = github-oidc

This file configures the “dev” profile with the host URL, client ID, and authentication type set to github-oidc. The client_id is the Service Principal in the Databricks workspace, configured as per the Databricks documentation. Ensuring these details are correctly set is crucial for successful authentication.

Expected Behavior

The expected behavior is a successful authentication with the Databricks workspace. When Terraform is initialized and a plan is created, the Databricks provider should authenticate using the provided GitHub OIDC credentials. This involves verifying the client ID, secret, and other configurations against the Databricks workspace settings. A successful authentication allows Terraform to read and manage resources within the Databricks environment.

Actual Behavior

In reality, the authentication process fails, resulting in the following error message:

Error: cannot read spark version: cannot read data spark version: failed during request visitor: github-oidc auth: databricks OAuth is not supported for this host. Config: host=https://foobar-dev.cloud.databricks.com, profile=dev, config_file=databricks/.databrickscfg.ci, ...... Env: DATABRICKS_CONFIG_FILE, ACTIONS_ID_TOKEN_REQUEST_URL, ACTIONS_ID_TOKEN_REQUEST_TOKEN

This error message indicates that the Databricks OAuth is not supported for the specified host. It also provides context on the configuration and environment variables being used. This error typically arises when the Databricks workspace is not correctly configured to support GitHub OIDC or when there are issues with the authentication flow.

Steps to Reproduce

To reproduce this issue, follow these steps:

  1. Prerequisites: Ensure all prerequisites outlined in the Databricks documentation for setting up GitHub OIDC are met. This includes creating a Service Principal in the Databricks workspace and configuring the necessary federation policies.
  2. Set up databrickscfg file: Configure the databrickscfg file with the correct client_id, host URL, and auth_type set to github-oidc.
  3. Run Terraform: Execute terraform plan within a GitHub Actions workflow or a local environment configured to use GitHub OIDC.

By following these steps, you can replicate the error and verify the issue. The next step involves identifying the root cause and implementing the appropriate solution.

Analyzing the Root Cause

To effectively resolve the “databricks OAuth is not supported for this host” error, we need to dissect the potential root causes. Several factors could contribute to this issue, including incorrect configuration, unsupported authentication methods, and misaligned settings between the Databricks workspace and the Terraform provider.

1. Databricks Workspace Configuration

One of the primary reasons for this error is an improperly configured Databricks workspace. GitHub OIDC authentication requires specific settings to be enabled and correctly configured within the Databricks workspace. If these settings are missing or misconfigured, the authentication process will fail. Key aspects to verify include:

  • Service Principal: Ensure that a Service Principal is created in the Databricks workspace. This Service Principal acts as the identity that Terraform uses to authenticate. The client_id in the databrickscfg file should correspond to this Service Principal.
  • Federation Policy: A federation policy must be in place to allow GitHub Actions to assume the Service Principal. This policy defines the conditions under which GitHub Actions can authenticate with Databricks. Incorrectly configured policies can block the authentication flow.
  • Workspace Settings: Verify that the workspace settings allow for GitHub OIDC authentication. This might involve enabling specific features or configuring allowed identity providers. Misconfigured workspace settings can prevent successful authentication.

2. Incorrect Provider Configuration

The Terraform provider configuration plays a crucial role in the authentication process. An incorrect provider configuration can lead to authentication failures, even if the Databricks workspace is correctly set up. Key areas to examine include:

  • Host URL: Ensure that the host URL in the databrickscfg file is accurate. An incorrect URL will prevent Terraform from connecting to the Databricks workspace.
  • Authentication Type: The auth_type in the databrickscfg file must be set to github-oidc. Any other value will cause the provider to use a different authentication method, leading to failure.
  • Profile Configuration: Verify that the profile specified in the Terraform provider block matches the profile in the databrickscfg file. Mismatched profiles will prevent the provider from using the correct credentials.

3. Unsupported Authentication Method

In some cases, the Databricks workspace might not support GitHub OIDC authentication for certain operations or hosts. If GitHub OIDC is not supported for the specific Databricks host, the authentication process will fail. Key considerations include:

  • Host Compatibility: Ensure that the Databricks host supports GitHub OIDC authentication. Some older Databricks deployments or specific regions might not fully support this authentication method.
  • Feature Availability: Verify that the specific features or operations you are trying to perform support GitHub OIDC authentication. Some operations might require alternative authentication methods.

4. GitHub Actions Configuration

When using GitHub Actions, the configuration of the workflow is critical for successful authentication. Incorrectly configured GitHub Actions workflows can prevent the proper exchange of tokens and credentials, leading to authentication failures. Key aspects to review include:

  • ID Token Permissions: Ensure that the GitHub Actions workflow has the necessary permissions to request an ID token. This involves setting the appropriate permissions in the workflow file.
  • Environment Variables: Verify that the required environment variables, such as ACTIONS_ID_TOKEN_REQUEST_URL and ACTIONS_ID_TOKEN_REQUEST_TOKEN, are correctly set. These variables are used to request and retrieve the ID token.
  • Workflow Steps: Ensure that the workflow steps are correctly sequenced and that the necessary actions are performed to authenticate with Databricks. Incorrectly sequenced steps can disrupt the authentication flow.

5. Provider Version Compatibility

The version of the Databricks provider used in your Terraform configuration can also impact authentication. Using an outdated or incompatible provider version can lead to authentication issues. Key considerations include:

  • Provider Version: Ensure that you are using a provider version that supports GitHub OIDC authentication. Older versions might not have this feature.
  • Terraform Version: Verify that your Terraform version is compatible with the Databricks provider version. Incompatible versions can lead to unexpected behavior.

By carefully analyzing these potential root causes, you can identify the specific issue in your configuration and implement the appropriate solution.

Solutions and Workarounds

Once the root cause of the “databricks OAuth is not supported for this host” error has been identified, implementing the correct solution is crucial. Below are several solutions and workarounds that address the common issues encountered when using GitHub OIDC with the Databricks provider.

1. Verify Databricks Workspace Configuration

Ensuring the Databricks workspace is correctly configured for GitHub OIDC is a primary step in resolving authentication issues. This involves checking the Service Principal, federation policy, and workspace settings.

  • Service Principal Configuration:

    • Confirm that a Service Principal has been created in the Databricks workspace.
    • Verify that the client_id in the databrickscfg file matches the Application ID (Client ID) of the Service Principal.
    • Ensure the Service Principal has the necessary permissions to perform the required operations within the Databricks workspace.

  • Federation Policy Configuration:

    • Review the federation policy attached to the AWS IAM role that the Service Principal will assume.
    • Ensure the policy allows GitHub Actions to assume the role based on the GitHub repository, organization, and workflow.
    • The policy should include conditions that verify the GitHub repository and workflow attempting to authenticate.

  • Workspace Settings Configuration:

    • Verify that the Databricks workspace allows GitHub OIDC authentication.
    • Check for any restrictions on the use of Service Principals or specific authentication methods.
    • Ensure there are no conflicting policies or settings that might interfere with the authentication process.

2. Correct Provider Configuration

The Terraform provider configuration must be accurate to ensure successful authentication. This includes verifying the host URL, authentication type, and profile configuration.

  • Host URL Verification:

    • Confirm that the host URL in the databrickscfg file is correct.
    • The URL should match the Databricks workspace URL and include the correct domain.
    • Ensure there are no typos or formatting errors in the URL.

  • Authentication Type Specification:

    • Verify that the auth_type in the databrickscfg file is set to github-oidc.
    • This setting explicitly tells the provider to use GitHub OIDC for authentication.
    • Any other value will result in a different authentication method being used, leading to failure.

  • Profile Configuration Alignment:

    • Ensure the profile specified in the Terraform provider block matches the profile in the databrickscfg file.
    • Mismatched profiles will prevent the provider from using the correct credentials.
    • The profile name should be consistent across both the Terraform configuration and the databrickscfg file.

3. Ensure Host Compatibility

Incompatibilities between the Databricks host and the GitHub OIDC authentication method can cause issues. Verify that the Databricks host supports GitHub OIDC.

  • Host Support Check:

    • Confirm that the Databricks host URL is compatible with GitHub OIDC authentication.
    • Some older Databricks deployments or specific regions might not fully support this authentication method.

  • Feature Availability Verification:

    • Ensure the specific features or operations you are trying to perform support GitHub OIDC authentication.
    • Some operations might require alternative authentication methods.

4. Configure GitHub Actions Workflow Correctly

When using GitHub Actions, the workflow configuration is critical for successful authentication. This involves setting the correct permissions, environment variables, and workflow steps.

  • ID Token Permissions Setup:

    • Ensure the GitHub Actions workflow has the necessary permissions to request an ID token.
    • This involves setting the appropriate permissions in the workflow file.
    • The permissions should include id-token: write to allow the workflow to request a JWT.

  • Environment Variables Configuration:

    • Verify that the required environment variables, such as ACTIONS_ID_TOKEN_REQUEST_URL and ACTIONS_ID_TOKEN_REQUEST_TOKEN, are correctly set.
    • These variables are used to request and retrieve the ID token.
    • GitHub Actions automatically sets these variables when the appropriate permissions are granted.

  • Workflow Steps Sequencing:

    • Ensure the workflow steps are correctly sequenced and that the necessary actions are performed to authenticate with Databricks.
    • Incorrectly sequenced steps can disrupt the authentication flow.
    • The steps should include initializing Terraform, authenticating with Databricks, and performing the desired operations.

5. Upgrade Provider and Terraform Versions

Using outdated or incompatible versions of the Databricks provider and Terraform can lead to authentication issues. Upgrading to the latest compatible versions can resolve these problems.

  • Provider Version Upgrade:

    • Ensure you are using a provider version that supports GitHub OIDC authentication.
    • Refer to the Databricks provider documentation for the latest version and compatibility information.

  • Terraform Version Upgrade:

    • Verify that your Terraform version is compatible with the Databricks provider version.
    • Incompatible versions can lead to unexpected behavior.

By implementing these solutions and workarounds, you can address the “databricks OAuth is not supported for this host” error and ensure successful authentication with the Databricks provider using GitHub OIDC.

Practical Examples and Code Snippets

To further illustrate the solutions, let’s look at some practical examples and code snippets that you can use to configure GitHub OIDC with the Databricks provider.

1. Terraform Configuration

Here’s an example of a Terraform configuration that specifies the required provider versions and the Databricks provider settings:

terraform {
  required_version = ">= 1.10"
  required_providers {
    databricks = {
      source  = "databricks/databricks"
      version = "1.84.0" # Use the latest version
    }
  }
}

provider "databricks" {
profile = "dev" # Specify the profile from databrickscfg
}


data "databricks_spark_version" "latest_lts" {
long_term_support = true
}

This configuration block ensures that you are using a compatible version of Terraform and the Databricks provider. Always use the latest provider version to leverage the newest features and bug fixes.

2. Databricks Configuration File

The Databricks configuration file (databricks/.databrickscfg.ci) should be set up as follows:

[dev]
host      = https://foobar-dev.cloud.databricks.com # Your Databricks workspace URL
client_id = xxxxxx-xxxx-xxxx-xxxx-xxxxxxxxx # Service Principal Application ID
auth_type = github-oidc # Authentication type

Ensure that the host, client_id, and auth_type are correctly specified. The client_id must match the Application ID of the Service Principal in your Databricks workspace.

3. GitHub Actions Workflow Configuration

Here’s an example of a GitHub Actions workflow configuration that sets up the necessary permissions and steps for authenticating with Databricks:

name: Terraform Plan

on:
push:
branches:
- main


permissions:
id-token: write # Request a JWT
contents: read


jobs:
terraform:
name: Terraform
runs-on: ubuntu-latest
environment: dev # Environment name


steps:
  - name: Checkout code
    uses: actions/checkout@v3

  - name: Setup Terraform
    uses: hashicorp/setup-terraform@v2
    with:
      terraform_version: 1.1.7 # Specify Terraform version

  - name: Initialize Terraform
    run: terraform init

  - name: Terraform Plan
    run: terraform plan

This workflow configuration includes the permissions block to request a JWT, which is necessary for GitHub OIDC authentication. The id-token: write permission is crucial for the workflow to authenticate with Databricks.

4. AWS IAM Federation Policy

The AWS IAM federation policy should allow GitHub Actions to assume the Service Principal based on the GitHub repository and workflow. Here’s an example policy:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowGithubOIDC",
      "Effect": "Allow",
      "Principal": {
        "Federated": "arn:aws:iam::<AWS_ACCOUNT_ID>:oidc-provider/token.actions.githubusercontent.com"
      },
      "Action": "sts:AssumeRoleWithWebIdentity",
      "Condition": {
        "StringEquals": {
          "token.actions.githubusercontent.com:aud": "sts.amazonaws.com",
          "token.actions.githubusercontent.com:sub": "repo:<GITHUB_ORG>/<GITHUB_REPO>:ref:refs/heads/main"
        }
      }
    }
  ]
}

Replace <AWS_ACCOUNT_ID>, <GITHUB_ORG>, and <GITHUB_REPO> with your actual values. This policy allows GitHub Actions to assume the role based on the specified conditions.

5. Debugging Commands

When troubleshooting, these commands can help identify issues:

  • terraform init: Initializes the Terraform working directory.
  • terraform plan: Creates an execution plan, showing the changes that Terraform will apply.
  • terraform apply: Applies the changes required to reach the desired state.

By using these examples and code snippets, you can configure GitHub OIDC with the Databricks provider more effectively and resolve authentication issues.

Conclusion

Successfully configuring Databricks authentication with GitHub OIDC requires a thorough understanding of the configurations involved and the potential pitfalls. The "databricks OAuth is not supported for this host" error can be frustrating, but by systematically reviewing the Databricks workspace settings, provider configuration, GitHub Actions workflow, and IAM policies, you can pinpoint and resolve the issue. Key takeaways include verifying the Service Principal, federation policy, host URL, authentication type, and permissions.

By following the solutions and workarounds outlined in this article, you can streamline your Databricks deployments and ensure a secure and efficient authentication process. Regular reviews and updates to your configurations will help prevent future issues and maintain a robust infrastructure automation pipeline. Embracing best practices for identity and access management will not only improve security but also enhance the overall reliability of your Databricks deployments.

Databricks, GitHub OIDC, Terraform, Authentication, AWS, Error, Troubleshooting, Configuration, Service Principal, IAM Policy, Workflow, GitHub Actions, Provider, OAuth, Authentication Error