Terraform vs CloudFormation: Comparing The Two Infrastructure As Code Offerings (2022)
Terraform vs CloudFormation
Infrastructure as code [IaC] has become increasingly popular over the past few years and there’s no wonder why. IaC, also known as software-defined infrastructure, is an IT setup that developers or operations teams can use to automatically manage and supply the technology stack for an application through software.
With IaC there’s no need to use a manual process to configure discrete hardware devices and operating systems. It is also one of the fundamentals of DevOps, which boosts the efficiency and quality of work. The two most used tools for implementing IaC on AWS are open-source tools Terraform and CloudFormation.
What is Terraform?
- Terraform permits you to define on-prem and cloud resources in readable configuration files that you can easily share, revise, and reuse.
- It provides a durable, consistent workflow to supply and manage all of your infrastructures.
- Terraform can manage low-level components such as:
– networking resources
How does Terraform work?
- Terraform can create and manage resources through its application programming interfaces (APIs) on cloud platforms and various services.
- Providers enable it to work with virtually any platform or service with an accessible API.
- The Terraform community works with more than 1700 providers and manages thousands of types of services and resources and the company continues to expand.
- You can find all publicly available providers on the Terraform Registry:
– Amazon Web Services (AWS)
– Azure, Google Cloud Platform (GCP)
The Core Terraform Workflow Consists of Three Stages:
- Write: Define your resources that could run through multiple cloud services and providers.
- Plan: Terraform will compile an execution plan outlining the infrastructure it will create, update, or destroy based on the existing infrastructure and your configuration.
- Apply: Once approved, Terraform will perform all the proposed operations in the correct sequence, and consider any resource dependencies.
- Manage Any Infrastructure
Terraform takes an indelible approach to infrastructure to reduce the complexity of modifying or updating your infrastructure and services. It also keeps track of your real infrastructure in a state file. This file will determine all the necessary changes that need to be made to your infrastructure, aligning it with your configuration files. These files describe the end state of your infrastructure. Because Terraform controls the underlying logic, you won’t need to write out detailed instructions to create resources. It will build a resource graph that regulates resource dependencies. It will create or modify non-dependent resources, helping you keep track of all your resources easily.
- Standardize Configurations
Terraform is highly efficient as it supports modules or reusable configuration components. Modules offer a hassle-free way to package and reuse code and are equivalent to the methods or functions in programming or scripting languages. Modules are considered a standard interface because they create resources by allocating inputs and returning outputs. This simplifies projects considerably by increasing readability and permitting teams to utilize logical blocks to organize infrastructure.
Another benefit of modules is that they can be sourced and shared into any Terraform project easily. Modules are typically used as an interface for managing and creating multiple resources. This significantly cuts down the number of duplicate code in a project, but copying and pasting sections of code around while only changing select parameters can be monotonous. By using input variables, you can customize the behavior of a module and, possibly, how it labels resources. Terraform modules can also return output, which can function as input into different modules or resources.
When running infrastructure of any size, there will undoubtedly be an overwhelming number of components and configurations. That can be tricky because there are so many subtle variations within the infrastructure used by different teams within an organization. This can further complicate things because the infrastructure may be span across a wide variety of topographies ranging from on-premise to numerous cloud vendors. As a result, organizing and maintaining the infrastructure is a complicated process.
What is AWS CloudFormation?
AWS CloudFormation offers businesses and developers a simple way to create a variety of related AWS and other resources. Developers can install and update databases, compute, and a variety of other resources in a straightforward, declarative style, removing the challenge of designating specific resource APIs. Cloudformation also manages resource lifecycles regularly, predictably, and safely. It also permits automatic rollbacks, automated state management, and management of resources for all accounts and regions.
CloudFormation allows you to spend more time focusing on your applications that run in AWS, and less time managing your resources. You can design a template that defines all the AWS resources that you desire including Amazon EC2 instances or Amazon RDS DB instances, etc. CloudFormation will take care of provisioning and configuring your resources. It also handles creating and configuring AWS resources, and figures out all dependency logistics.
- Simplify Infrastructure Management
To build a scalable web application that includes a backend database, you may use an Amazon Relational Database, Service database instance, or an Auto Scaling group. After creating resources with the service to a provision that you’ve chosen, you will have to configure them to collaborate. These extra steps can complicate and slow down the process of getting your application off the ground. CloudFormation allows you to create a template or modify an existing one. A template defines all your resources and all their components.
Using that template to create a CloudFormation stack will permit the service full control over the Auto Scaling group, load balancer, and database. Your AWS resources will be fully functional once the stack has been created successfully. Deleting the stack is simple, but keep in mind that deleting a stack means deleting all the resources it holds. All in all, CloudFormation makes managing a collection of resources in a single unit an easy experience.
- Quickly Replicate Your Infrastructure
If your application requires additional availability, you could potentially replicate it in numerous regions so that if one region becomes unavailable, people can still use your application elsewhere. This is easier said than done. It can be challenging to replicate your application because it also requires you to duplicate your resources. You must record every resource required by your application while managing and configuring those resources in each region.
CloudFormation templates are great because you can reuse them to create your resources consistently and repeatedly. To do this, you have to define your resources once and then provision those resources continuously in multiple regions. CloudFormation is constantly adapting, and recent updates and new options make it possible to have multiple methods to create resources. These include utilizing AWS CDK for coding in advanced level languages, detecting configuration drift, and importing existing resources. There is now a Registry that makes it convenient to create custom types that have a lot of the core benefits of Cloudformation.
CloudFormation Four Main Concepts
- A template is either a JSON or YAML-formatted text file that describes the intended state of all the resources you need to successfully run your application. They are comprised of the following:
- An optional list of template parameters (input values supplied at stack creation time)
- An optional list of output values (e.g., the complete URL of a web application)
- An optional list of data tables is used to look up static configuration values (e.g., AMI names).
- The list of AWS resources and their configuration values
2. template file format version number
3. A stack enforces and manages all the resources in your template which permits the state and dependencies of those resources to be managed together.
4. A changeset is a preview of all the updates that will be carried out by stack operations to create, update, or remove resources.
5. A stack set is a group of stacks you manage simultaneously that can copy a group.