
Automate IaC with Terraform and Ansible

23.04.2024
Infrastructure as Code (IaC)
Infrastructure as Code (IaC) is a key practice in modern DevOps that enables the management and provisioning of computing resources through machine-readable configuration files, rather than manual processes. By using IaC, teams can standardize their infrastructure setups, minimize configuration drift, and streamline the deployment process.
Automation plays a pivotal role in this practice, eliminating human errors and ensuring consistency across environments. The rise of cloud computing has further amplified the need for IaC, as it allows teams to manage infrastructure at scale efficiently.
In this post, I'll walk you through how I automated my infrastructure using two powerful tools: Terraform and Ansible. We'll explore why these tools are popular in the DevOps community, how they can be used together, and the best practices to follow for successful automation.
This guide will cover the setup process, writing configuration files, and integrating Terraform with Ansible for a robust automation workflow. By the end of this post, you should have a clear understanding of how to implement IaC using these tools effectively.
Why Choose Terraform and Ansible for IaC?
Overview of Terraform
Terraform, developed by HashiCorp, is a powerful open-source tool that enables users to define and provision data center infrastructure using a high-level configuration language. One of Terraform’s key strengths is its ability to manage infrastructure across multiple cloud providers through a single interface, making it an ideal choice for multi-cloud environments.
Terraform uses a declarative approach, allowing you to define the desired state of your infrastructure. The tool then handles the underlying complexities to achieve this state, making infrastructure management more predictable and less prone to errors.
Overview of Ansible
Ansible, created by Red Hat, is an open-source automation tool that is particularly strong in configuration management, application deployment, and task automation. Unlike Terraform, which is focused on infrastructure provisioning, Ansible is designed to automate the configuration of your servers once they have been provisioned.
Ansible is agentless, meaning it doesn’t require any software to be installed on the target machines. This simplifies the setup process and reduces the overhead associated with managing infrastructure.
Complementary strengths of Terraform and Ansible
Terraform and Ansible are often used together because they complement each other well. Terraform excels at provisioning infrastructure, such as setting up virtual machines, networking components, and storage. Ansible, on the other hand, shines in configuring these resources, ensuring they are set up according to your specifications.
By combining Terraform and Ansible, you can create a fully automated infrastructure pipeline, from provisioning to configuration. This reduces manual intervention and enhances the reliability of your deployments.
Setting up Terraform for infrastructure Automation
Installing Terraform
Before you can start using Terraform, you need to install it on your machine. Terraform is available for all major operating systems, including Windows, macOS, and Linux. The installation process is straightforward and typically involves downloading the binary, adding it to your system’s PATH, and verifying the installation with a simple command.
Once installed, you can begin writing your first Terraform configuration. Terraform configurations are written in HashiCorp Configuration Language (HCL), which is designed to be human-readable and easy to understand.
Writing your first Terraform configuration
A basic Terraform configuration file typically includes providers, resources, and variables. Providers are the services that Terraform will interact with, such as AWS or Google Cloud. Resources define the infrastructure components, like virtual machines or databases, that Terraform will manage.
Here’s a simple example of a Terraform configuration file that provisions an AWS EC2 instance:
This configuration tells Terraform to create a t2.micro EC2 instance using a specific Amazon Machine Image (AMI) in the US West 2 region.
Using Terraform to provision cloud infrastructure
After writing your configuration file, the next step is to initialize Terraform, which downloads the necessary provider plugins. Then, you can run the terraform apply
command to provision the infrastructure as defined in your configuration.
Terraform’s plan and apply commands are powerful tools that allow you to preview the changes that will be made to your infrastructure before they are applied, giving you confidence in the automation process. Once the apply process is complete, Terraform will maintain a state file, which tracks the resources it manages.
Integrating ansible for configuration management
Installing Ansible
To begin using Ansible, you'll need to install it on your control machine. Ansible supports various operating systems and can be installed using package managers like apt
for Ubuntu or yum
for CentOS. Installation is quick and straightforward, allowing you to get started with writing playbooks almost immediately.
Playbooks are the heart of Ansible, defining the tasks that should be automated across your infrastructure. They are written in YAML, which is both easy to read and write.
Writing Ansible playbooks for configuration management
An Ansible playbook is a YAML file that contains a series of tasks for configuring your infrastructure. Each task specifies the desired state of a particular aspect of your system, such as installing packages, managing files, or configuring services.
Here’s a simple example of an Ansible playbook that installs Nginx on a remote server:
This playbook will connect to all servers in the webservers
group and install the Nginx package.
Automating infrastructure with Terraform and Ansible
With Terraform handling the provisioning and Ansible managing the configuration, you can create a robust automation pipeline. Typically, Terraform is used first to provision the infrastructure, and then Ansible takes over to configure it.
For example, Terraform might be used to create an EC2 instance, and Ansible could be used to install and configure software on that instance. This separation of responsibilities allows you to modularize your infrastructure code and reuse components as needed.
You can integrate Terraform and Ansible by using Terraform’s local-exec
provisioner to run Ansible playbooks after resources have been provisioned. This approach ensures that your infrastructure is not only provisioned but also configured correctly and consistently.
Best practices for IaC with Terraform and Ansible
Version control for IaC
Storing your IaC configurations in version control systems like Git is essential for collaboration and change tracking. By versioning your Terraform and Ansible files, you can maintain a history of changes, roll back to previous states if necessary, and collaborate more effectively with your team.
Version control also supports Continuous Integration/Continuous Deployment (CI/CD) pipelines, where infrastructure changes are automatically tested and deployed, further enhancing the reliability of your infrastructure.
Managing secrets and sensitive data
When automating infrastructure, it’s crucial to manage secrets, such as API keys and passwords, securely. Terraform and Ansible both support integrations with secret management tools like HashiCorp Vault or AWS Secrets Manager, allowing you to store and retrieve sensitive data securely.
Avoid hardcoding sensitive information directly in your configuration files. Instead, use environment variables, encrypted files, or secret management tools to handle this data.
Ensuring idempotency in configurations
Idempotency ensures that running your Terraform configurations or Ansible playbooks multiple times will always result in the same infrastructure state. This is a critical aspect of IaC, as it guarantees consistency across deployments.
Terraform and Ansible both emphasize idempotency. For example, Terraform’s declarative syntax inherently ensures that the desired state is achieved without creating duplicate resources. Similarly, Ansible modules are designed to check the current state before making changes, ensuring that your configurations remain consistent.
Automating Infrastructure as Code with Terraform and Ansible provides a powerful, scalable approach to managing cloud infrastructure. By leveraging Terraform’s provisioning capabilities and Ansible’s configuration management, you can create a seamless, automated workflow that enhances both efficiency and reliability.
Throughout this guide, we’ve covered the setup process, writing configurations, and integrating these tools for a complete IaC solution. As you implement these practices, you’ll find that automating infrastructure not only saves time but also reduces the risk of human error and ensures consistency across environments.
Whether you’re just starting with IaC or looking to refine your automation processes, Terraform and Ansible offer the tools and flexibility you need to manage your infrastructure effectively. As you continue to develop your IaC skills, consider exploring additional tools and techniques to further enhance your automation workflows.