Fix Charles Zipp Azure DevOps Terraform Backend Issue

The Charles Zipp Azure DevOps Task Provider failing to initialize Terraform AzureRm backend is commonly caused by configuration changes in newer Terraform versions and extension conflicts. To resolve this issue, you need to update your backend configuration parameters, use the correct task versions, and resolve any extension conflicts in your Azure DevOps pipeline.

Contents

• Common Error Messages
• Primary Causes of Failure
• Step-by-Step Solutions
• Alternative Approaches
• Best Practices
• Troubleshooting Checklist

Common Error Messages

When the Charles Zipp Azure DevOps Task Provider fails to initialize the AzureRm backend, you typically encounter one of these error messages:

• Invalid backend configuration argument: The backend configuration argument “arm_subscription_id” given on the command line is not expected for the selected backend type
• Terraform backend initialization for AzureRM only support service principal authorization: This indicates authentication issues with the service principal
• Tasks with versions are not valid: Extension version conflicts causing task ambiguity

These errors occur primarily due to changes in Terraform’s backend configuration syntax starting from version 0.15.0 and conflicts between different Terraform extensions in Azure DevOps.

Primary Causes of Failure

1. Backend Configuration Parameter Changes

Terraform 0.15.0 introduced changes to the AzureRM backend configuration parameters. The older parameter names like arm_subscription_id are no longer valid and have been replaced with new names.

2. Extension Version Conflicts

Multiple Terraform extensions in Azure DevOps can cause conflicts:

• Charles Zipp extension
• Microsoft’s official extension
• Jason Johnson’s newer extension

When multiple extensions are installed, you may encounter task naming ambiguities where TerraformInstaller@0 becomes ambiguous.

3. Service Principal Authentication Issues

The AzureRM backend initialization requires proper service principal authentication, and configuration errors in the service connection can cause initialization failures.

Step-by-Step Solutions

Solution 1: Update Backend Configuration Parameters

The most common fix is to update your backend configuration to use the new parameter names introduced in Terraform 0.15.0:

- task: TerraformTaskV2@2
  displayName: 'Terraform Init'
  inputs:
    provider: 'azurerm'
    command: 'init'
    backendServiceArm: 'ARM'
    backendAzureRmResourceGroupName: 'example'
    backendAzureRmStorageAccountName: 'example'
    backendAzureRmContainerName: 'example'
    backendAzureRmKey: 'example'
    workingDirectory: '$(System.DefaultWorkingDirectory)/terraform'

If you’re using the older parameter names, update them and run terraform init -reconfigure to force a reconfiguration of the backend.

Solution 2: Use the Correct Task Version

Upgrade from the older TerraformTaskV1@0 to TerraformTaskV2@2 which has better support for newer Terraform versions:

- task: TerraformTaskV2@2
  displayName: 'Terraform Init'
  inputs:
    provider: 'azurerm'
    command: 'init'
    backendServiceArm: 'ARM'
    workingDirectory: '$(System.DefaultWorkingDirectory)/terraform'
    backendAzureRmResourceGroupName: 'example'
    backendAzureRmStorageAccountName: 'example'
    backendAzureRmContainerName: 'example'
    backendAzureRmKey: 'example'

Solution 3: Resolve Extension Conflicts

If you have multiple Terraform extensions installed, this can cause task naming conflicts:

1. Uninstall conflicting extensions: Remove the Charles Zipp and Microsoft extensions if you’re using Jason Johnson’s newer extension
2. Specify full task names: Instead of using the short form, use the full task name to avoid ambiguity:

- task: charleszipp.azure-pipelines-tasks-terraform.azure-pipelines-tasks-terraform-cli.TerraformCLI@0
  displayName: 'Terraform Init'
  inputs:
    command: 'init'
    backendType: 'azurerm'
    workingDirectory: '$(System.DefaultWorkingDirectory)/terraform'
    backendServiceArm: '$(ServiceConnection)'
    backendAzureRmResourceGroupName: '$(resourceGroup)'
    backendAzureRmStorageAccountName: '$(storageAccount)'
    backendAzureRmContainerName: '$(container)'
    backendAzureRmKey: '$(key)'

Solution 4: Force Reconfiguration

If you’ve updated your configuration but still encounter issues, force a reconfiguration by adding the -reconfigure flag:

- task: TerraformTaskV2@2
  displayName: 'Terraform Init'
  inputs:
    provider: 'azurerm'
    command: 'init'
    commandOptions: '-reconfigure'
    backendServiceArm: 'ARM'
    workingDirectory: '$(System.DefaultWorkingDirectory)/terraform'
    backendAzureRmResourceGroupName: 'example'
    backendAzureRmStorageAccountName: 'example'
    backendAzureRmContainerName: 'example'
    backendAzureRmKey: 'example'

Alternative Approaches

Use Jason Johnson’s New Azure Pipeline Terraform Extension

Some users have successfully resolved the issue by switching to Jason Johnson’s newer extension:

- task: ms-devlabs.custom-terraform-tasks.custom-terraform-installer-task.TerraformInstaller@0
  displayName: 'INSTALL TERRAFORM VERSION'
  inputs:
    terraformVersion: '$(terraform_ver)'

- task: TerraformCLI@0
  displayName: 'TERRAFORM INIT'
  inputs:
    command: 'init'
    backendType: 'azurerm'
    workingDirectory: '$(workingDir)'
    backendServiceArm: '$(ServiceConnection)'
    backendAzureRmResourceGroupName: '$(resourceGroup)'
    backendAzureRmStorageAccountName: '$(storageAccount)'
    backendAzureRmContainerName: '$(container)'
    backendAzureRmKey: '$(key)'

Manual Terraform Installation

For complete control, consider installing Terraform manually in your pipeline:

- task: charleszipp.azure-pipelines-tasks-terraform.azure-pipelines-tasks-terraform-installer.TerraformInstaller@0
  displayName: 'install'
  inputs:
    terraformVersion: '0.15.0'

- task: charleszipp.azure-pipelines-tasks-terraform.azure-pipelines-tasks-terraform-cli.TerraformCLI@0
  displayName: 'init'
  inputs:
    command: 'init'
    workingDirectory: '$(System.DefaultWorkingDirectory)/terraform'
    backendServiceArm: 'ARM'
    backendAzureRmResourceGroupName: 'example'
    backendAzureRmStorageAccountName: 'example'
    backendAzureRmContainerName: 'example'
    backendAzureRmKey: 'example'

Best Practices

1. Keep Terraform Version Updated

Use the latest stable version of Terraform to ensure compatibility with the latest backend configurations.

2. Use Specific Task Versions

Always specify exact task versions rather than using wildcard versions like 0.* to avoid unexpected changes.

3. Validate Service Principal Configuration

Ensure your service principal has the necessary permissions to access the storage account and resource group for state management.

4. Test Configuration Locally

Before deploying to Azure DevOps, test your Terraform configuration locally to ensure the backend initialization works correctly.

5. Use Environment-Specific Configurations

Separate your backend configurations for different environments to avoid conflicts and improve maintainability.

Troubleshooting Checklist

If you’re still experiencing issues, follow this systematic troubleshooting approach:

1. Check Terraform Version: Ensure you’re using a compatible version (0.15.0 or later recommended)
2. Verify Backend Configuration: Confirm all backend parameters are correctly spelled and use the latest syntax
3. Test Service Connection: Validate your Azure service connection works correctly
4. Check Extension Conflicts: Ensure you don’t have multiple Terraform extensions installed
5. Review Pipeline Logs: Look for specific error messages and check the full command being executed
6. Test Locally: Run the same Terraform commands locally to isolate the issue
7. Check Permissions: Verify the service principal has appropriate RBAC permissions

Sources

1. HashiCorp Terraform Issue #28378 - Backend configuration changes in Terraform 0.15
2. Stack Overflow - Azure DevOps Terraform task fails with Error: Invalid backend configuration argument
3. HashiCorp Discuss - Azure DevOps init going wrong backend configuration
4. Reddit - Pipeline release error with conflicting Terraform extensions
5. Stack Overflow - YAML Azure DevOps TerraformInstaller is ambiguous
6. Microsoft Azure Pipelines Extensions Issue #944 - Backend configuration argument error
7. Stack Overflow - Executing Terraform in Azure pipelines fails because of authentication

Conclusion

The Charles Zipp Azure DevOps Task Provider failing to initialize Terraform AzureRm backend is typically resolved by following these key steps:

1. Update backend configuration parameters to use the new syntax compatible with Terraform 0.15.0+
2. Use TerraformTaskV2@2 instead of older task versions for better compatibility
3. Resolve extension conflicts by either removing conflicting extensions or specifying full task names
4. Force reconfiguration using the -reconfigure flag when updating backend configurations
5. Consider switching to Jason Johnson’s newer extension if issues persist with the Charles Zipp extension

The most effective solution is usually updating your backend configuration parameters and ensuring you’re using the correct task version. Always test your changes in a development environment before deploying to production pipelines. If you continue to experience issues, consider migrating to the newer Azure Pipeline Terraform extension by Jason Johnson, which has been reported to resolve many of these compatibility problems.