A Beginner's Guide to Infrastructure as Code (IaC) with Terraform

When I first started to code, I remember staring at my computer screen, fingers hovering over the keyboard as I had to update a load balancer configuration—a seemingly simple change to the infrastructure. 

But even so, I was anxious. One mistake or typo could take down our system. 

Managing infrastructure shouldn't feel so risky. There had to be a better way. 

Infrastructure as Code (IaC), with tools like Terraform, changed this. 

IaC allows you to manage and set up infrastructure using machine-readable files instead of touching hardware or using configuration tools. You write code to automate the process and this code replaces manual infrastructure setup.

In fact, the 2023 State of DevOps report found that organizations using IaC, achieve 30% higher organizational performance. And 68% of respondents saw faster development cycles after adopting platform engineering practices, which often include IaC.

Now, you might be reading this because you've had a similar experience as I did. Maybe you were tired of manual configuration errors. Perhaps your company is growing, and you want to scale your infrastructure management. This guide will help you.

We'll explore the basics of Infrastructure as Code(IaC) with Terraform and help you gain a solid conceptual understanding. But first, what exactly is Terraform and IaC?

What Is IaC and Terraform?

Infrastructure as Code (IaC) is a dramatic shift in how developers manage and provision computing resources. IaC treats infrastructure configuration like software, so instead of manually setting up physical servers, networks, and other IT components, you define the setup in code. This code becomes a single source of truth for your infrastructure, helping you automate deployments, ensure consistency across the board, and scale your setup easily with no infrastructure drift.

But then, what’s Terraform and how does it relate to IaC?

Terraform is an open-source tool created by HashiCorp that brings IaC to life. It is a declarative language  that helps you define your infrastructure as code. 

You specify what you want—like a cluster of web servers and a load balancer—and Terraform figures out how to make it happen, whether you are using AWS, Azure, Google Cloud, or a mix of providers.

Terraform understands the current state of your infrastructure and makes only the necessary changes to achieve your desired state. This means you can update your infrastructure over time, adding new components or modifying existing ones. 

Is there any benefit to using Terrform?

Benefits of Using Terraform for IaC

Terraform is like a Swiss Army knife for infrastructure management. Its versatility and ease of use have made it the go-to language for DevOps teams. Here are some of the key advantages of using Terraform:

1. Development velocity: Platform engineering practices, especially IaC with Terraform, accelerate development speed. Organizations using platform engineering for over three years see even greater improvements. 53% of these teams report that the speed has improved "a great deal” compared to only 35% of newer adopters.

2. Improved security: Terraform integrates security directly into the infrastructure from the outset. Over 55% of users confirm that IaC practices strengthen overall infrastructure security. Also, with full security integration using Terraform, you canremediate critical vulnerabilities within a day 45% of the time, compared to only 25% for those with low integration.

3. Better efficiency: 59% of respondents stated improved efficiency and productivity as a direct benefit of platform engineering practices, which often incorporate IaC tools like Terraform. This aligns with Terraform's ability to automate repetitive tasks and streamline infrastructure management.

4. Multi-cloud deployment: Platform teams want to go cloud-native with 40% citing it as their key goal. And managing infrastructure across multiple cloud providers is easy with Terraform. Public cloud infrastructure increases flexibility by 22% compared to localized setups. Terraform's multi-cloud capabilities help organizations maximize this advantage across different providers.

5. Support for self-service capabilities: Terraform aligns well with the trend towards self-service platforms. Highly evolved DevOps organizations tend to offer a wide variety of self-service capabilities, including infrastructure provisioning and Terraform becomes the foundation of that setup.

6. Standardization and reduced duplication: Terraform's modular approach and reusable configurations contribute to increased standardization. 53% of developers state that standardization reduced duplication of work in the workplaces. 

7. State management and collaboration: Terraform's state management capabilities support the collaborative nature of modern DevOps practices. 63% of organizations have at least one self-service internal platform, which often relies on tools like Terraform for infrastructure management.

These examples highlight just a few of Terraform's many benefits. As you begin using it, you will discover even more ways it can optimize your infrastructure management processes.

Getting Started with Terraform

Let’s now jump into the steps to setup Terraform so you can get started implementing it. 

Installing Terraform

You need Terraform on your computer before you can use it. Downloading Terraform is easy because it lives in a single file.

1. Go to the official Terraform website (https://www.terraform.io/downloads.html) and get the right package. Make sure it works with your operating system.

2. Download the package, then extract its contents and put them in a directory of your choice

3. You will want to access Terraform easily. Add the directory with the Terraform contents to your system's PATH. This lets you run Terraform from anywhere using your terminal.

4. Open your terminal. Type "terraform." If you were successful, you will see Terraform's help information.

That’s it, Terraform is now installed on your computer.

Setting Up Your First Terraform Project

With Terraform installed, you can begin your first project. Here's how to set up a basic Terraform configuration:

1. Make a new folder for your project.

2. Create a new file with a ".tf" extension inside the folder (for example, "main.tf"). This file will hold your Terraform code. Let's make a simple configuration that creates an AWS EC2 instance:

1. Go to your project directory in your terminal and run "terraform init". This prepares your Terraform files and downloads the necessary plugins.

2. Run "terraform plan" to view the changes Terraform will make. This command only shows you the potential changes; it doesn't apply them yet.

3. If the plan looks correct, run "terraform apply" to create the resources defined in your configuration. Terraform will show you the plan again and ask for your confirmation.

Congratulations! You used Terraform to provision your first resource. While this example is basic, it shows the fundamental workflow of using Terraform.

Understanding Terraform Basics

Let’s now explore the fundamentals of Terraform one by one—starting with what configuration files actually are.

Configuration Files

Terraform configurations are written in HashiCorp Configuration Language (HCL) and describe exactly how you want your infrastructure to look. They detail the resources you want, their settings, and how they connect.

A typical Terraform configuration usually consists of one or more .tf files within a directory. When you use Terraform commands, it reads all these files. It then builds a dependency graph based on the resources you've defined.

Here’s a simple example of a Terraform configuration file:

This tells Terraform to use the AWS provider. It sets the default region to "us-west-2" and creates an AWS EC2 instance. This instance uses the specified AMI and instance type.

Terraform configurations are declarative so you describe the desired end state and Terraform figures out how to make it happen. This differs from imperative programming where you specify every step.

This declarative approach offers several advantages:

• Idempotency: Applying the same configuration multiple times always yields the same result. This makes your infrastructure predictable and reduces inconsistencies over time.

• Parallelization: Terraform understands the end goal. This allows it to determine which resources it can create, modify, or destroy concurrently. The result is faster infrastructure operations.

• Dry runs: You can use the terraform plan command to preview changes before applying them. This helps you catch potential problems early.

Terraform configurations can include several block types:

• Provider blocks: These define which providers your configuration will use (e.g., AWS, Azure, GCP). You also specify any global settings for those providers here.

• Resource blocks: These define the individual pieces of your infrastructure, like EC2 instances, VPCs, or DNS records.

• Data blocks: Use these to fetch information from providers for use in your configuration. An example is querying for the latest AMI.

• Variable blocks: These let you parameterize your configuration, making it more reusable and adaptable.

• Output blocks: Use these to export values from your configuration. Other Terraform configurations or external tools can then use them.

As your infrastructure becomes more complex, you'll likely use multiple .tf files which helps organize different parts of your configuration. Terraform will automatically read and combine all these files into a single configuration later.

State Management

Terraform keeps track of the resources it creates in a state file (usually terraform.tfstate). Think of this file as the single source of truth for your infrastructure. 

When you run terraform apply, Terraform follows these steps:

1. It reads the current state file to understand existing resources.

2. It compares the current state to the desired state you defined in your configuration files.

3. It figures out what changes are needed to reach the desired state.

4. It executes those changes and updates the state file along the way.

This ensures Terraform always knows the current state of your infrastructure and it can then make precise, incremental changes as needed. The state file is necessary for Terraform to work correctly so make sure that you store it safely and take backups at regular intervals in case of a loss.. 

Terraform supports various backends:

• S3: Stores the state file in an Amazon S3 bucket.

• Azure Blob Storage: Stores the state file in an Azure Blob Storage container.

• GCS: Stores the state file in a Google Cloud Storage bucket.

• Terraform Cloud: HashiCorp's managed service for storing state files and running Terraform operations.

Here's how to configure an S3 backend in Terraform:

With this configuration, Terraform will store its state file in the “my-terraform-state” S3 bucket, under the key “directory-path/to/the/key”.

Terraform Plan and Apply Lifecycle

The terraform plan and terraform apply commands let you preview and execute changes to your infrastructure safely and predictably.

Terraform Plan

Unless you disable it, Terraform first refreshes its understanding of the current state when you run terraform plan. It then determines the necessary actions to achieve the desired state you defined in your configuration files.

Do note that this command doesn't make any actual changes. It simply shows you what Terraform will do. You can review the plan before anything happens, helping you spot potential errors or unwanted modifications.

Here’s an example output from terraform plan:

This plan shows that Terraform will create a new AWS EC2 instance with the specified AMI. The + indicates this is a new resource.

Terraform Apply

Once you've reviewed the plan and are happy with the proposed changes, use the terraform apply command. This command executes the plan and applies the changes.

By default, terraform apply asks you to confirm you want to proceed. You can skip this prompt using the --auto-approve flag. Just remember to be absolutely sure about the outcome before using this flag.

Here's an example of applying a Terraform configuration:

After the apply completes, your infrastructure will match the state described in your configuration files.

One of the key benefits of Terraform's plan and apply lifecycle is its focus on safe and predictable changes. Reviewing the plan before applying helps you catch potential issues early as Terraform tracks your infrastructure's state, making only the necessary modifications.

This contrasts with some other infrastructure management tools. They might require you to specify your entire infrastructure every time, leading to potential inconsistencies over time.

These concepts—configuration files, state management, and the plan and apply lifecycle—form the foundation of working with Terraform. Everything you build will be based on these basics.

However, the core workflow remains constant:

• Write declarative configuration files.

• Let Terraform manage the state.

• Use plan and apply to manage your infrastructure safely and predictably over time.

How to Use Terraform Modules?

Terraform modules are a powerful way to organize and reuse your infrastructure code. Let's explore how to create and implement these valuable components. 

Creating and Using Modules

As your infrastructure becomes more complex, managing it with a single Terraform configuration can feel overwhelming. This is where modules simplify things. 

A Terraform module is essentially a set of Terraform configuration files grouped within a single directory. 

These modules become your building blocks: they let you create reusable components, organize your code better, and manage parts of your infrastructure as self-contained units.

Think of a typical module structure like this. 

Don’t worry if you don’t fully understand this right now. Just look at it as a sample directory structure of how modules and terraform configuration files are stored.

In this setup, you have a root module defined by the main.tf, variables.tf, and outputs.tf files in the main directory. The modules directory houses subdirectories for each of your infrastructure components, like VPC, EC2, and RDS. Each of these subdirectories represents a separate module.

You can use a module within another Terraform configuration. Use a module block to do this:

The source argument points to the module's location. Here, it's a relative path on the same machine, but it could also be a remote source like a Git repository or the Terraform Registry.

Benefits of Modules

Modules offer several advantages for your Terraform configurations:

• Reusability: Modules let you package and reuse common configurations across your projects. This saves you time and minimizes repetitive code.

• Encapsulation: They hide complexity by allowing you to manage related resources as a single unit.

• Organization: Breaking down your configuration into modules makes your code cleaner and easier to understand.

• Versioning: You can version your modules. This lets you safely update and iterate on your infrastructure over time.

• Sharing: Modules can be shared within your team or publicly. This fosters collaboration and helps standardize infrastructure deployments.

The Terraform Registry (https://registry.terraform.io/) offers a vast collection of pre-built modules for common infrastructure elements and these existing modules can significantly speed up your infrastructure development.

Best Practices for IaC with Terraform

Now that you’ve understood the basics of Terraform for IaC, let’s look at the best practices for implementing IaC with Terraform. 

Adopt a GitOps Workflow for Version Control and Collaboration

Managing Terraform configurations effectively means adopting a GitOps workflow. This approach makes Git the single source of truth for your infrastructure and applications, just like your code.

You store your Terraform configurations in a Git repository to benefit from the version control and collaboration features. This approach lets you manage infrastructure code like application code. 

You can use pull requests, code reviews, and automated testing. Here is an example of a typical GitOps workflow with Terraform:

Source

1. Developers make a new branch for their infrastructure changes. They then open a pull request.

2. The CI/CD pipeline automatically runs terraform plan. This previews the changes.

3. After review and approval, the team merges the changes into the main branch.

4. The CI/CD pipeline then runs terraform apply. This applies the changes to the infrastructure.

This workflow ensures that all changes to your infrastructure are tracked and reviewed. It also helps make sure that you apply changes in a controlled way—you will always have an audit trail.

Use a Remote Backend for State Management

Terraform state keeps track of the resources Terraform creates. It also makes sure that Terraform can update or destroy those resources.

The state is stored locally by default using a file named terraform.tfstate. This works fine for one person. 

However, it can cause problems for teams. If multiple people run Terraform at the same time, they can overwrite each other's changes and corrupt the state file.

To avoid these issues, use a remote backend to store your state. It stores the state file in a shared location. It could be Amazon S3, Azure Blob Storage, or any other cloud setup that you already have. 

They often have locking mechanisms that prevent concurrent modifications and protect the integrity of your state file.

Use Modules for Reusability and Maintainability

Terraform modules are a great way to package and reuse common configurations. You can easily create reusable Terraform code to reduce duplication and make your configurations easier to maintain. It also reduces duplication and promotes consistency.

A well-designed module should:

1. Have a clear purpose.

2. Encapsulate related resources and configurations.

3. Expose a clear interface (inputs and outputs).

4. Be independently testable.

5. Be versioned and stored in a separate repository

When creating modules, follow naming and structure conventions. HashiCorp recommends a standard module structure. This includes main.tf, variables.tf, and outputs.tf files.

Use a Consistent Naming Convention

Try to establish a consistent naming convention for your Terraform resources. This makes them easier to maintain and understand. Here are a few pointers for good naming:

1. Be descriptive and meaningful.

2. Include information about the resource's purpose, environment, and/or team ownership.

3. Use a consistent format and separator (e.g., hyphens or underscores).

4. Be compatible with the naming restrictions of your cloud provider.

Here’s an example naming convention:

For instance:

Maintaining a consistent naming standard across the team also makes it easier to understand each resource's purpose. It helps you identify resources belonging to a specific project or environment and avoid naming collisions when there is a large team working on the same projects.

Common Challenges and Solutions

While Terraform is a powerful tool, it’s not without its challenges. Here are some common issues you may encounter and how to address them:

1. State drift: Your infrastructure's actual state should always match your Terraform state file. When they don't align, that's called drift. It often happens when someone manually changes your infrastructure outside of Terraform. Remember to regular run terraform plan and terraform apply to find and fix drift.

2. Collaboration conflicts: Working with a team on the same Terraform configuration can lead to conflicts. To avoid headaches, use a remote backend like Terraform Cloud or AWS S3 with DynamoDB. And along with all the locking mechanisms, there is no substitute for clear communication and coordination within your team.

3. Complex dependencies: As your infrastructure grows, dependencies between resources can become complex and hard to manage. Terraform has a built-in dependency graph to help you understand and visualize these dependencies.

4. Performance issues: Large infrastructures can make Terraform operations slow and cumbersome. One way to speed things up is to break your configuration into smaller modules. You can also use terraform plan with the --target flag to focus on specific resources. 

5. Provider limitations:  Terraform supports many providers. However, not all provider features may be available. Read the documentation for the providers you are using. Make sure you understand any limitations.

The Next Step in Simplified Infrastructure

Implementing IaC will be difficult at first. Remember your first time learning to code? 

The syntax seemed strange, and the ideas were hard to grasp. Algorithms didn’t make sense.

But your confidence grew with every line of code you wrote and every bug you fixed. 

Learning Terraform is going to be quite similar. It's just another way to interact with your infrastructure and like learning any language, you’ll get better as you write more code. But, this will take time for you, as well as everyone, who will be interacting with infrastructure on your team. 

What if you could implement IaC without the difficulty of learning it from scratch? That is where Facets comes in.

Facets acts like an expert you can access anytime to guide you through the cloud. You can easily model your architecture, launch environments, and handle daily tasks with its no-code platform. Facets simplifies infrastructure management and frees you to focus on what's important—creating and deploying great software.

Want to experience no-code infrastructure automation to speed up your development workflows? Try Facets for free!