Using Rover to visualize Terraform resource dependencies

Introduction

As the complexity of infrastructure grows, understanding the intricate web of dependencies within your Terraform configurations can become a daunting task. Visualizing these dependencies can greatly enhance your ability to understand, debug, and optimize your infrastructure. This is where Rover, a powerful tool for visualizing Terraform dependencies, comes into the picture. In this tutorial, we will guide you through the process of using Rover to visualize Terraform resource dependencies, from basic usage to advanced techniques.

Getting Started with Rover

Before diving into the specifics, it’s important to ensure that you have Terraform and Rover installed on your system. Rover can be installed via various package managers or directly from its GitHub repository. Once installed, you can begin the journey of visualizing your Terraform configurations.

$ brew install rover

Verify the installation:

$ rover --version

Basic Visualization

To start visualizing your Terraform configurations with Rover, navigate to your Terraform directory where your configuration files are located. Using Rover is as simple as executing the following command:

$ rover -planPath ./path/to/terraform/plan/file

This command generates a visualization of your current Terraform plan. The output is an SVG file which illustrates the dependencies between your resources. To view this file, you can use any web browser or an SVG viewer.

Exploring Dependencies

After generating the basic visualization, you might want to delve deeper into understanding the specific dependencies. Rover provides options to customize the visualization to better meet your needs. For instance, to highlight only specific resources, you can use filtering options:

$ rover -planPath ./path/to/terraform/plan/file -filter=aws_instance

This command will narrow down the visualization to only show dependencies related to AWS instances.

Advanced Techniques

For more advanced users, Rover offers several options to further refine the visualization. You can, for example, use terraform graph combined with Rover to customize the graph’s aesthetics or to include/exclude specific types of connections between resources:

$ terraform graph | rover -filter=aws_vpc

This command pipelined with `terraform graph` allows for even greater customization and focusses on AWS VPC resources.

Integrating Rover into CI/CD Pipelines

One of the most powerful applications of Rover is its integration into Continuous Integration/Continuous Deployment (CI/CD) pipelines. This enables you to generate and review dependency visualizations as part of the review process for infrastructure changes. Here’s a simple example of how Rover can be integrated into a GitHub Actions workflow:

name: Generate Terraform Plan Visualization

on: [pull_request]

jobs:
  visualize:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Set up Terraform
      uses: hashicorp/setup-terraform@v1
    - name: Generate Plan
      run: terraform plan -out=tfplan
    - name: Visualize Plan
      run: rover -planPath tfplan -output plan.svg
    - name: Upload Visualization
      uses: actions/upload-artifact@v2
      with:
        name: Terraform Plan Visualization
        path: plan.svg

This snippet from a GitHub Actions workflow illustrates how Rover can be used to generate and upload a visualization of the Terraform plan upon every pull request, aiding in the review process.

Conclusion

Through its straightforward command-line interface and integration capabilities, Rover facilitates a deeper understanding of your Terraform managed infrastructure. By visualizing resource dependencies, you can fine-tune configurations, anticipate potential conflicts, and streamline review processes. Leveraging Rover effectively can transform your infrastructure management workflows into a more efficient and error-resistant operation.