Terraform – Definition and meaning

What is Terraform?

Terraform is an open-source infrastructure-as-code tool developed by HashiCorp and used to manage, plan and provision cloud-based infrastructures. With Terraform, developers and IT administrators can create reusable, declarative configurations to efficiently provision and manage various cloud resources.

Why use Terraform?

Terraform has gained popularity in recent years because it offers the following advantages:

• Declarative configuration: Terraform uses a declarative syntax that allows you to define the desired infrastructure, while the tool automatically takes the necessary steps to create and manage that infrastructure.
• Infrastructure management across different cloud providers: Terraform can be used to manage resources across multiple cloud services (e.g. AWS, Google Cloud, Azure), simplifying the management of multi-cloud environments.
• Version control: Since Terraform configurations are stored in text files, they can be integrated into version control systems such as Git, which improves collaboration and traceability.

How does Terraform work?

Terraform works in several steps to provide the desired infrastructure:

1. Planning: developers create Terraform configuration files that define the desired resources and their properties. The terraform plan command generates an action plan that shows what changes will be made to the infrastructure.
2. Provisioning: After reviewing the plan, the terraform apply command can be executed to create or modify the resources defined in the previous step.
3. Management: Terraform tracks the status of the provisioned infrastructure in a status file. Changes to the configuration files can be applied repeatedly with terraform apply to adjust the infrastructure accordingly.

Advantages of Terraform in infrastructure management

Terraform has many advantages that make it a popular tool for DevOps teams:

• Reusability: infrastructures can be built modularly by creating different modules for recurring configurations.
• Resource plan visualisation: Terraform provides a visual representation of resource dependencies, making it easier to understand the infrastructure.
• Automated rollback: In the event of difficulties during deployment, Terraform can automatically roll back to the previous stable version, minimising downtime.

Updates and changes with Terraform

If changes to the infrastructure are required, this is usually done by making adjustments to the existing Terraform configuration files. After the update, the terraform plan and terraform apply commands can be executed again to realise the changes safely and efficiently.

Illustrative example on the topic: Terraform

Imagine a company is planning to deploy a new software application in the cloud. The team uses Terraform to define a complete infrastructure consisting of various components such as servers, databases and networks. The team creates a main configuration file that describes all resources and defines dependencies between them.

After writing these files, the team uses the terraform plan command to get an overview of the upcoming changes. They see that Terraform is ready to create three virtual machines, a database instance and a load balancer. After reviewing this plan, the team runs terraform apply and sees in real time how the infrastructure comes to life in the cloud. If adjustments are needed in the future, the team can simply modify the configuration file and run the steps again to implement the changes.

Conclusion

Terraform is an indispensable tool for modern infrastructure management. It enables organisations to provision and manage resources quickly, securely and automatically. Its ability to integrate with various cloud providers and the use of version control systems ensure flexibility and transparency in infrastructure management. If you would like to learn more about related concepts such as DevOps or cloud computing, take a look at our other posts!