Secrets Management with Terraform

Last Updated on August 7, 2025 by Arnav Sharma

In DevOps, the secure management of secrets is critical to protecting infrastructure and ensuring compliance. Integrating Azure DevOps, Terraform Cloud, and Azure Key Vault offers a robust solution for deploying infrastructure securely. Additionally, understanding the various methods to manage secrets in Terraform enhances this integration, providing multiple layers of security, such as implementing a secrets engine. Here’s how you can effectively utilize these tools and methodologies for optimal secrets management, including the integration of secret stores for Terraform using secrets securely.

Key Methods for Managing Secrets in Terraform

1. Environment Variables

Environment variables are a fundamental method for injecting secrets at runtime. This approach ensures that sensitive data remains outside of Terraform configuration files. This is especially critical in environments where the codebase is accessible by multiple users or teams.

Steps to Implement:

• Set environment variables in your CI/CD pipeline configuration (e.g., in Azure DevOps).
• Configure Terraform to read these variables during runtime, ensuring they are never hard-coded in your files, thus securely managing the secrets within Terraform.

2. Terraform Cloud

Terraform Cloud offers enhanced security by providing encrypted storage for sensitive data. Utilizing its environment variables section allows you to manage secrets that Terraform can access during execution.

Steps to Implement:

• Create and configure a Terraform Cloud workspace.
• Add secrets as environment variables within the workspace, marking them as sensitive to ensure they are encrypted and handled securely.

3. HashiCorp Vault

HashiCorp Vault is designed specifically for secure secrets management. It provides robust controls to manage access to sensitive data and integrates seamlessly with Terraform to supply secrets dynamically during runtime, showcasing the benefit of managing the secrets effectively.

Steps to Implement:

• Set up a Vault server and configure the necessary policies and roles to store and manage secrets in a secure manner.
• Use Terraform provider for Vault to fetch secrets dynamically when Terraform runs, thus keeping sensitive data out of your configurations.

4. Cloud Provider Secrets Managers

Cloud-specific secrets managers, such as AWS Secrets Manager, Azure Key Vault, and Google Secret Manager, offer built-in integration with their respective cloud environments, providing a secure and efficient way to manage and access secrets.

Steps to Implement:

• Choose a secrets manager and create your secrets within the service.
• Configure Terraform to retrieve secrets from these services during deployment using the appropriate provider plugins. Leverage secret stores like AWS Secrets Manager and HashiCorp Vault for enhanced security.

5. Encrypted Files

For teams that prefer keeping secrets within their version control system, using tools like git-crypt, Blackbox, or GPG offers a way to encrypt files containing sensitive data.

Steps to Implement:

• Encrypt files containing secrets using your chosen tool, ensuring that new secret information is securely handled.
• Configure Terraform to decrypt these files on-the-fly during deployments.

6. Terraform State Encryption

Encrypting Terraform state files is crucial as they can contain sensitive data. By using server-side encryption features provided by cloud storage solutions, you can secure these files effectively. This includes encrypting secrets in secrets manager for added protection.

Steps to Implement:

• Store your Terraform state in a cloud storage service that supports encryption (e.g., AWS S3 with SSE-KMS).
• Enable server-side encryption to protect the state files stored in the cloud.

7. Sensitive Variables

Terraform supports marking variables as sensitive, which prevents their values from being visible in the output after running terraform apply.

Steps to Implement:

• Mark any sensitive variable in Terraform configurations as sensitive to ensure their values do not appear in logs or console output.
• Understand that while the values are hidden in output, they are still present in the state file and should be handled with additional security measures.

Integrating Secrets Management into Your DevOps Workflow

Azure DevOps for CI/CD

Utilize Azure DevOps to automate your Terraform deployments. Set up Pipelines that handle the automation and orchestration of your deployments and securely fetch secrets from Azure Key Vault during the build or release phases.

Workflow Integration:

• Configure Azure Pipeline to retrieve secrets from Azure Key Vault using service principals, showcasing an effective way of using secrets in your CI/CD workflow.
• Ensure these secrets are injected into the Terraform runtime environment without logging or saving them in any configuration files.

Terraform Cloud for Secure Execution

Terraform Cloud plays a crucial role in securely executing Terraform plans and applies. By managing secrets through environment variables within Terraform Cloud, you ensure that all operations are performed within a controlled and secure environment.

Workflow Integration:

• Set up and manage your infrastructure as code (IaC) configurations in Terraform Cloud, employing the best practices for storing and managing secrets.
• Leverage its secure execution environment to manage and apply your Terraform configurations without exposing secrets.

Azure Key Vault for Centralized Secrets Management

Azure Key Vault should be your centralized hub for managing cryptographic keys, certificates, and other secrets. Its integration with both Azure DevOps and Terraform Cloud simplifies access and management of secrets across your deployment pipelines.

Workflow Integration:

• Store and manage all your application and infrastructure secrets in Azure Key Vault.
• Configure access policies to control who can access these secrets and under what circumstances.

By following these detailed steps and integrating the powerful capabilities of Azure DevOps, Terraform Cloud, and Azure Key Vault, you can significantly enhance the security and compliance of your infrastructure deployments, providing a secure, scalable, and efficient DevOps environment.