Comprehensive IaC comparison: Terraform vs Pulumi vs CloudFormation

AWS CloudFormation, Pulumi, and Terraform are the most popular IaC options cloud developers use to provision AWS cloud resources. Like most stack choices, picking the right tool comes down to the resources and services you require, the support you’re looking for, and the price you’re willing to pay.

AWS CloudFormation and Terraform are mature and widely adopted systems, whereas Pulumi, a relatively new entrant, brings additional features and takes a comprehensive approach to cloud engineering. We compared the tools based on features and the user experience, so you can pick the one that suits you the best.

How does IaC help my startup?

As a startup, being agile is often the top priority. From having lean teams to using open-source and free dev tools, it’s all about moving fast. One thing that is often overlooked and yet takes a considerable chunk of your dev team’s time is infra overheads. Replicating infra and having clear visibility into what is running at any point in time is essential. Setting up an infrastructure that meets your customer's needs, is reliable, and can be scaled takes a lot of effort. This valuable time is taken away from developing your core application.

We compare AWS CloudFormation and Terraform based on their core offerings, developer experience, integrations and extensibility, testing and deployment, and pricing.

Core features

Provisioning infra as code is the common goal among these tools. Here’s how they do it differently. Understanding their state management, what configuration languages are supported, and what makes them unique are the first steps in getting to know these tools.

Developer experience

The three IaC tools have ecosystems of varying maturity. This also can be seen in the type and number of resources covered. Things like time to learn, modularity, and secret management can be seen below.

Integrations and extensibility

IaC templates are the blueprints of your infra; thus, having extensibility is vital to support third-party and dynamically add custom resource types. We also see how soon they support new AWS resources and services.

Testing and deploying

IaC tools simplify testing and can be deployed quickly with your existing CI/CD pipelines. Tools like AWS CloudFormation also offer automatic and manual rollback capabilities.

Pricing

Pricing is often the most important decision factor for most startups. Here’s how they compare. They all offer paid support and enterprise version with additional features which can come in handy as your startup scales. Terraform is often the better choice for enterprise teams.

*Though the tools are free to use, the resources provisioned will cost you money. Spend less by leveraging the 100+ AWS services in their free tier.

Here’s the ultimate list of AWS free credit deals for your startup.

Deploying AWS resources using IaC

To give you an idea of what the code looks like, we have examples of deploying an S3 bucket using AWS CloudFormation, Terraform, and Pulumi.

S3 bucket using AWS CloudFormation

As the only platform-specific tool on the list, AWS CloudFormation is limited deploying AWS resources. Almost all AWS CloudFormation functionality can also be achieved using their UI.

AWSTemplateFormatVersion: "2010-09-09"
Description: Simple cloud formation for bucket creation and configuration

Resources:
  S3Bucket:
    Type: 'AWS::S3::Bucket'
    DeletionPolicy: Retain
    Properties:
      BucketName: my-bucke
            VersioningConfiguration:
        Status: Enabled

S3 bucket using Terraform

Terraform uses the Hashicorp Configuration Language, which is very intuitive to use. There is also excellent documentation available for all the AWS resources.

resource "aws_s3_bucket" "my-bucket" {
   bucket = "test-s3"
   acl = "private"
   versioning {
      enabled = true
   }
   tags = {
     Name = "My bucket"
     Environment = "Dev"
   }
}

S3 bucket using Pulumi

Pulumi’s packages make it easy to create and manage an s3 bucket easily and in the language of your preference. The below example shows the code in YAML format.

resources:
  bucket: test-s3
    type: aws:s3:Bucket
    properties:
      acl: private
      tags:
        Environment: Dev
        Name: My bucket

Further reading

Here are some informative articles that touch on this topic.

1. https://www.cncf.io/blog/2021/04/06/cloudformation-vs-terraform-which-is-better/
2. https://cloudonaut.io/cloudformation-vs-terraform/
3. https://thenewstack.io/terraform-vs-cloudformation-which-is-better-for-you/
4. https://www.pulumi.com/docs/intro/vs/cloud-templates/cloudformation/
5. https://www.pulumi.com/docs/intro/vs/terraform/