Terraform Variable Management at Scale: Centralizing IaC with Variable Sets and Provider Registry in Harness IaCM

Infrastructure as Code (IaC) has made provisioning infrastructure faster than ever, but scaling it across hundreds of workspaces and teams introduces new challenges. Secrets get duplicated. Variables drift. Custom providers become hard to share securely.

That’s why we’re excited to announce two major enhancements to Harness Infrastructure as Code Management (IaCM):

Variable Sets and Provider Registry built to help platform teams standardize and secure infrastructure workflows without slowing developers down.

Variable Sets: Centralized Configuration Without the Chaos

Variables in Infrastructure as Code store configuration values like credentials and environment settings so teams can reuse and customize deployments without hardcoding. However, once teams operate dozens or hundreds of workspaces, variables quickly become fragmented and hard to govern. Variable Sets provide a single control plane for configuration parameters, secrets, and variable files used across multiple workspaces. In large organizations, hundreds of Terraform or OpenTofu workspaces share overlapping credentials and configuration keys such as Terraform variable sets or OpenTofu variable sets. Traditionally, these are duplicated, making credential rotation, auditing, and drift prevention painful.

Harness IaCM implements Variable Sets as first-class resources within its workspace model that are attachable at the account, organization, or project level. The engine dynamically resolves variable inheritance based on a priority ordering system, ensuring the highest-priority set overrides conflicting keys at runtime.

Core Capabilities

• Hierarchical Inheritance Graph: Workspaces resolve variables based on an explicit priority order defined by the platform team, with the highest-priority Variable Set taking precedence. Conflicts are clearly surfaced in the UI, showing overridden values and the exact source of each variable.

• Type and Scope Support: Handles both regular key-value pairs and .tfvars files. Variables can reference Harness Connectors (e.g., Vault or AWS Secrets Manager) for secure retrieval at execution. Both Terraform variable sets and OpenTofu variable sets can also be attached to Workspace Templates.
  
  
• Change Propagation: When a variable changes, Harness automatically lists all affected workspaces via reference tracking, allowing controlled rollouts or bulk updates.
  
  
• Access Control and Auditing: Only users with workspace edit permissions can change precedence; future RBAC plans extend granular edit and view rights. Every modification is recorded in IaCM audit logs.
  
  
• Runtime Execution: Conflict resolution occurs at Terraform runtime for variable files but design-time for inline variables giving predictable behavior and faster validation.

For enterprises running hundreds of Terraform workspaces across multiple regions, Variable Sets give platform engineers a single, authoritative home for Vault credentials. When keys are rotated, every connected workspace automatically inherits the update by eliminating manual edits, reducing risk, and ensuring compliance across the organization. It’s a fundamental capability for terraform variable management at scale.

Provider Registry: Secure Distribution for Custom Providers

Provider Registry introduces a trusted distribution mechanism for custom Terraform registry and OpenTofu provider registry. While the official Terraform registry and OpenTofu Provider Registry caters to public providers, enterprise teams often build internal providers to integrate IaC with proprietary APIs or on-prem systems. Managing these binaries securely is non-trivial.

Harness IaCM solves this with a GPG-signed, multi-platform binary repository that sits alongside the Module Registry under IaCM > Registry. Each provider is published with platform-specific artifacts (macOS, Linux, Windows), SHA256 checksums, and signature files.

Core Capabilities

• Integration with Policy as Code: Platform teams can enforce which providers are allowed within configurations using OPA-based policy checks in the pipeline.
  
  
• Secure by Default: Each provider binary is signed with a GPG key and verified during download to prevent tampering.
  
  
• Cross-Platform Resolution: At tofu init or terraform init, Harness detects the OS/architecture and automatically delivers the correct binary without manual setup.
  
  
• Version Consistency: Strict semantic version matching (v1.0.0 ≠ v1.0.1) prevents runtime mismatches and enforces dependency integrity
  
  
• Faster Internal Integrations: Publish internal APIs or custom integrations as reusable providers.
  
  
• No Manual Management: Developers can seamlessly use approved providers directly in configurations without managing binaries locally.

For any enterprise teams that build a custom provider to integrate OpenTofu with their internal API. Using Harness Provider Registry, they sign and publish binaries for multiple platforms. Developers simply declare the provider source in code, Harness handles signature verification, delivery, and updates automatically. Together with the Module Registry and Testing for Modules, Provider Registry completes the picture for trusted, reusable infrastructure components helping organizations scale IaC with confidence.

Why These Features Matter

Harness IaCM already provides governed-by-default workflows with centralized pipelines, policy-as-code enforcement, and workspace templates that reduce drift. Now, with Variable Sets and Provider Registry, IaCM extends that governance deeper into how teams manage configuration and custom integrations. These updates make Harness IaCM not just a Terraform or OpenTofu orchestrator, but a secure, AI infrastructure management platform that unifies visibility, control, and collaboration across all environments.

Harness’s broader IaCM ecosystem includes:

• Multi-IaC support: Terraform, OpenTofu, Terragrunt, Ansible (with more coming soon).
  
  
• Cost visibility: Pre-deployment cost estimation and post-deployment tracking.
  
  
• GitOps-native workflows: Approvals and policy checks built into pull requests.
  
  
• AI-powered policy generation: Intelligent guardrails to accelerate standards enforcement.
• AI-driven pipeline generation and failure analysis: leveraging the same intelligent capabilities used across Harness pipelines to streamline authoring and troubleshoot issues faster.

How IaCM is different

Unlike standalone tools today, Harness IaCM brings a unified, end-to-end approach to infrastructure delivery, combining:

• A single workspace model for every IaC tool
• Centralized variable and provider management giving platform teams consistent governance and control.
• AI-native governance with policy generation
• Native security scanning through integrated STO and SCS, ensuring misconfigurations and vulnerabilities are caught early in the SDLC.
• A unified SDLC pipeline experience, where infrastructure, application, security, and compliance checks all run through the same pipeline model.
• A developer-friendly experience with Harness IDP, offering self-service templates, golden paths, and standardized guardrails that make infrastructure safe and accessible for every team.

This all-in-one approach means fewer tools to manage, tighter compliance, and faster onboarding for developers while maintaining the flexibility of open IaC standards. Harness is the only platform that brings policy-as-code, cost insight, and self-service provisioning together into a single developer experience.

Get Started Today

Explore how Variable Sets and Provider Registry can streamline your infrastructure delivery all within the Harness Platform. Request a Demo to see how your team can standardize configurations, improve security, and scale infrastructure delivery without slowing down innovation.

‍