Constructing and managing your cloud infrastructure manually can be a quite daunting task especially when you are operating as a distributed team. Being forced to comply with all the frequent changes and updates, the IT teams find it challenging to properly provision, configure and deploy applications and resources when needed and fix bugs on the go. This might cause your system to bog down and letting you waste time and resources that you could spend in improving your cloud infrastructure. Infrastructure as Code (IaC) is specifically introduced to counter situations like these.

IaC, or a software-defined infrastructure, is an IT setup wherein developers or IT teams can automatically manage and provision the technology stack for an application, rather than using a manual process to configure hardware devices and operating systems. IaC allows you to leverage configuration files written in high-level descriptive coding languages to automate the management of your cloud infrastructure. Considered as the cornerstone of DevOps, IaC is designed to improve the agility and efficiency within organizations.

With more and more organizations having jumped on the bandwagon, there are a plenty of cloud marketplaces with IaC tools. Unfortunately, there’s no solitary IaC tool that offers everything end-to-end and you are forced to evaluate and pick one from a list of services that suits your organization best. AWS CloudFormation and Terraform are 2 such IaC services that would top your lists.

AWS CloudFormation

AWS CloudFormation is an Amazon web service with a common language that allows you to create, provision, and manage a plethora of Amazon services and third-party resources in a secure and repeatable manner. The in-built AWS CloudFormation designer makes it easier to manage, monitor, and test your cloud infrastructure.

With CloudFormation, the onus is on the tool to figure out which AWS services need to be provisioned in a siloed fashion. Once deployed, by leveraging CloudWatch, you can destroy and modify your AWS resources, allowing you to control your own cloud infrastructure.

Terraform

Developed by HashiCorp, Terraform is an open-source, cloud-agnostic IaC tool that helps users with setting up and provisioning datacenter infrastructure. The tool enables you to use AWS modules and third-party modules in the same cloud infrastructure.

The tool has the ability to run clusters comprising high and low-level component modules simultaneously. It also codifies APIs into declarative configuration files that can be shared within the organization.

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The Comparison

Both the IaC tools have distinctive features to offer and organizations might find one tool better than the other depending on their requirements or cloud infrastructure needs. To help you pick one of these two, we compare CloudFormation and Terraform on the basis of state management, modularity, integrated logging, and safeguarding and rollback capabilities.

State Management

  • Terraform stores the infrastructure state on the provisioning computer by default or in a remote site. When the state is stored remotely, Terraform stores the file in a custom JSON format, serving as a map for the IaC tool describing the resources it manages and how those resources should be configured.
  • AWS CloudFormation, on the other hand, allows users to provision resources automatically and perform regular drift detection on their provisioned infrastructure. The tool collects AWS resources and dependencies to bundle them together into stacks. A stack can encompass the AWS resources for a web application. If the application gets deleted, the tool also deletes the stack. Organizations can modify the provisioned resources without a complete rebuild when you manage a stack state.

Modularity

  • AWS CloudFormation leverages a system called “nested stacks.” They act as building blocks for your AWS cloud infrastructure and allow users to import and export standard configuration settings. With multiple configurations of resources used for different applications or infrastructure, you can create a dedicated template for such resources, which you can import into every stack that needs the resource.
  • Terraform has the edge over AWS CloudFormation when it comes to modularity. Being a cloud-agnostic IaS tool, it includes native support for many third-party modules through “providers” or plugins.

The tool also uses modules, which allow complex configurations to remain readable by managing related parts. Reusing modules minimizes errors and time taken in rewriting your configurations. As Terraform publishes modules online, you can gain access to community knowledge and experience, while reducing time taken to write and debug configuration files.

Integrated Logging

This is one of the best features available in any IaC tool. Integtrated logging allows developers to manage, monitor, and test their cloud infrastructure and rectify any errors if detected.

Rollbacks and Safeguards

Both the IaC tools come with deletion protection. This means that you can’t delete resources in use as dependencies in other applications. Henceforth, the chances of accidentally breaking your infrastructure are minimal.

  • CloudFormation always backs up data stores before modifying or deleting them. In case of infrastructure failures due to manual updates occur, CloudFormation will automatically rollback your infrastructure.
  • Terraform, on the other hand, does not support automatic rollbacks under any circumstances. You can deploy fixes yourself or you can also prevent a rollback by using the command terraform plan that displays a list of all possible upcoming changes before executing them. The command can also be used to complete dry runs of an update and double-check the output.

Differences in Infrastructure

Here’s how the two IaC solutions fit into your infrastructure.

Terraform CICD pipeline

The above diagram depicts how Terraform integrates with the standard CI/CD pipeline. Terraform is responsible for provisioning instances on Amazon’s ECS cluster in the CD part of the pipeline.

The infographic below depicts the overall workflow of how CloudFormation works.

how CloudFormation works

CloudFormation’s workflow can be summarized in 4 steps:

  1. Writing your code in the CloudFormation template
  2. Save the template in any code repository, preferably in an S3 bucket
  3. Leverage AWS CLI or the browser console to create the stack
  4. The final output is displayed in the form of infrastructure stacks

Who’s the winner?

As mentioned earlier, consider your team and infrastructure requirements before taking a final call. Both IaC tools exhibit compelling features and offer comprehensive state management and automated logging. If you’re solely relying on AWS resources, CloudFormation should be the best fit. However, if you’re into third party resources, we’d recommend Terraform.

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Sreyesh Sarma