Скачать или смотреть Fixing Terraform Init Errors in Azure DevOps Pipelines with Self-Hosted VMSS Agents

Learn how to resolve the 'Failed to find terraform tool in paths' error in Azure DevOps pipelines using VMSS self-hosted agents by properly installing Terraform and managing workspace checkouts.
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This video is based on the question https://stackoverflow.com/q/79484705/ asked by the user 'Roy' ( https://stackoverflow.com/u/29889897/ ) and on the answer https://stackoverflow.com/a/79485343/ provided by the user 'Alvin Zhao - MSFT' ( https://stackoverflow.com/u/16600319/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem

When running Terraform workflows in Azure DevOps pipelines—especially with self-hosted VMSS agents—you might encounter the error:

[[See Video to Reveal this Text or Code Snippet]]

This typically occurs during the terraform init step in a deploy stage after an approval gate, even if the plan stage worked fine.

Why Does This Happen?

Different Agents for Different Stages:
VMSS (Virtual Machine Scale Sets) agents can run jobs on different virtual machines. If your plan and apply stages run on different agents, the Terraform executable installed in one job isn't available in the other.

TerraformInstaller Task Scope:
The TerraformInstaller@ 1 task downloads Terraform binaries only for the current job into $(Agent.ToolsDirectory). It does not install Terraform globally on the VMSS instances.

Deployment Job Checkout Behavior:
Unlike standard jobs that run with checkout: self by default, Azure DevOps deployment jobs use download: current by default to fetch pipeline artifacts. If no artifacts were published from the previous stage, the Terraform files aren't available in deployment jobs unless explicitly checked out.

How to Fix It

To make your Terraform deployment stage work reliably:

1. Install Terraform in Every Job

Despite installs in the plan job, add the TerraformInstaller@ 1 task again in the deploy job:

[[See Video to Reveal this Text or Code Snippet]]

This ensures Terraform binary is available to all pipeline jobs.

2. Explicitly Check Out Source Code in Deployment Job

Add a checkout step to pull your Terraform configs:

[[See Video to Reveal this Text or Code Snippet]]

This makes your Git repository files available to the deployment job, unlike the default artifacts-only download.

3. Verify Setup with Debug Steps

Add a quick script to validate environment variables, paths, and Terraform version:

[[See Video to Reveal this Text or Code Snippet]]

This helps confirm that Terraform is installed and the source directory is populated.

Summary

When dealing with VMSS self-hosted agents and multi-stage Azure DevOps pipelines for Terraform:

Remember that TerraformInstaller must run in each job individually.

Use checkout: self in deployment jobs to access Terraform files.

Validate your environment with debug commands.

This practice ensures terraform init and subsequent steps run smoothly regardless of which agent runs the job.

Additional Tips

Consider creating a VMSS image with Terraform pre-installed for consistent environment.

Use pipeline artifacts to pass built state or plans between stages if needed.

Applying these changes will eliminate the "Failed to find terraform tool in paths" error and streamline your Terraform deployment pipelines.