Infrastructure automation is a rapidly evolving field.

And one of the most popular tools for implementing it is Terraform.

Terraform is an open-source tool developed by HashiCorp, and it is used for building, changing, and versioning infrastructure safely and efficiently. With Terraform, you can define your infrastructure as code and deploy it in a repeatable and predictable manner. 

While that’s great, you can enhance the outcomes by following certain tips and best practices. These help you make the most of Terraform. 

In this blog, we’ll explore 10 must-know Terraform tips for infrastructure automation.

• Use a Version Control System to Manage Your Infrastructure Code
• Use Terraform Modules to Organize Your Infrastructure Code
• Use Workspaces to Manage Multiple Environments
• Understand How Terraform State Files Work
• Use the Terraform Graph Command to Visualize Your Infrastructure
• Use Terraform Variables to Parameterize Your Infrastructure
• Use Terraform Providers to Interact with Cloud Services
• Use the Terraform Plan Command to Preview Changes
• Use Terraform Remote Backends for Collaboration
• Use Terraform Modules from the Community

Using a version control system (VCS) is an essential best practice for managing infrastructure as code. VCS allows you to

• Keep track of changes made to your Terraform code
• Collaborate with your team, and
• Revert to previous versions if something goes wrong.

Git is the most popular VCS, and Terraform integrates well with it.

By using a VCS, you can manage infrastructure code like any other codebase. With Git branches, for example, you can work on new features or bug fixes and then merge the changes to the main code later.

Similarly, Git tags can be used to mark important milestones or releases. By including a descriptive commit message while making changes, you can also ensure that other team members understand what you did, why, and how.

Modules are a way to encapsulate reusable Terraform code. Modules can be used to create reusable building blocks for infrastructure resources, such as virtual machines, databases, or load balancers. Modules can be shared across different Terraform configurations and can be versioned separately.

With modules, you can avoid code duplication and manage changes in a much simpler manner.

Say, for example, you need to create multiple virtual machines with the same configuration. Then you can create a module for the virtual machine and reuse it across different Terraform configurations.

Even if you need to update the virtual machine configuration later on, you can make the change once in the module and all the virtual machine configurations will be automatically updated.

Terraform workspaces allow you to manage multiple environments, such as development, staging, and production, from a single Terraform configuration. And there is a separate state file for each workspace. This means that you can manage multiple versions of your infrastructure at the same time.

Workspaces help avoid mistakes while deploying changes to production and also avoid code duplication. 

This is because all the changes can be tested in the staging (or development environment) first. And once everything is correct, the changes can be deployed to production. Thus, mistakes can be eliminated. And because you can reuse Terraform configurations across different environments, you don’t need to write codes again and again.

Terraform offers Terraform state files, which can be used to track the current state of your infrastructure. These state files contain information about all the resources created by Terraform including virtual machines, networks, and storage accounts. With the use of state files, you can determine what changes need to be made to your infrastructure while running Terraform. 

Remember: Keep the state files in a safe and accessible location. Either you can store them locally or use object storage services. 

Local storage makes sharing and collaborating with others difficult. Thus, storing state files remotely on Amazon S3 or Azure Blob Storage is a widely used option. Cloud storage can also protect your state files against the chances of data loss. 

The Terraform graph command can be used to visualize the dependencies between resources in your Terraform configuration. The graph command generates a visual representation of the resources and their dependencies. This makes it easier to understand the impact of changes to your infrastructure.

With the graph command, you can avoid making changes that can have a cascading impact.

Let’s consider an example. Say, you want to remove a resource. Now, that resource might be required somewhere else.

With the graph command, you’ll be able to see the impact of the changes you are going to make. And this can help you avoid unintended consequences and ensure that your infrastructure changes are safe.

Terraform variables can be used to define values that are used throughout your configuration, such as the number of virtual machines to create, the size of a virtual machine, or the region to deploy to.

In short, variables allow parameterizing the infrastructure configuration. Thus, with the use of variables, it becomes extremely simple to manage your infrastructure configuration. 

Suppose you need to change the number of virtual machines you’re deploying. With variables, you can simply update the value of a variable rather than directly edit the configuration directly. Also, it becomes easier to reuse your configuration across different environments.

Terraform providers are used for interacting with cloud services, such as Amazon Web Services (AWS), Microsoft Azure, or Google Cloud Platform (GCP). Providers translate Terraform code into API requests that can be executed by these cloud services.

Thus, using providers makes cloud service interactions easier. 

How?
By abstracting away the details of the API and thus, making it easier to write infrastructure code. 

Providers also make switching between cloud services easier. This is because the Terraform code remains the same even if the cloud service changes.

The Terraform plan command lets you preview changes before they are made to your infrastructure. It generates a summary of the changes that will be made. 

The summary includes: 

• Resources that will be created, 
• Resources that will be modified, and 
• Resources that will be destroyed. 

Knowing all this clearly helps avoid costly mistakes that can result in blowing up the entire infrastructure. With the summary, you can also identify errors in configuration and any unwanted consequences of the changes you are planning to make. 

Further, the plan command can also be used to share the proposed changes with others in your team for review or approval.

Terraform remote backends allow you to store your state file remotely, which can make it easier to collaborate with others. Remote backends can be used to store your state file in a central location that is accessible to all members of your team. This can make it easier to collaborate on infrastructure code and ensure that everyone is working with the same version of the state file.

Using remote backends can also help protect against data loss. If your state file is stored locally and your computer crashes, you could lose all of your changes. Storing your state file remotely can help protect against this type of data loss.

There is a large community of Terraform users who create and share modules for common infrastructure resources. Using modules from the community can save you time and help you avoid mistakes. Community modules are usually well-tested and can be used as building blocks for your infrastructure code.

Using community modules can also help you learn best practices for writing Terraform code. By examining the code in community modules, you can learn how other users are writing their Terraform code and apply those best practices to your own code.

By following the aforementioned tips, you can ensure that your infrastructure changes are predictable and repeatable and that your infrastructure code is easy to maintain and update.

And if you work with Terraform experts, their experience and guidance will help you better utilize Terraform and not just use pre-established best practices but also develop your own best practices for infrastructure management and automation.