Master AWS CloudFormation : A Comprehensive Guide

It's easy to imagine how much work it would take to set up AWS for app or service deployment manually. Setting up each AWS resource separately makes it more likely that someone will make a mistake or do something inconsistent.

CloudFormation is a tool for automating Amazon Web Services (AWS) infrastructure. It makes it easy to provision, manage, and release AWS resources in a consistent, reliable, and auditable way.

Read on to learn about the features, benefits, and best practices of using AWS CloudFormation for application deployment. Let's read on to discover.

Introduction to AWS CloudFormation

AWS CloudFormation simplifies the process of creating models for deploying AWS resources. You no longer have to spend time managing resources. Instead, you can focus on making your AWS-hosted apps better.

With AWS CloudFormation, you can automate the process of setting up AWS by making a template with a list of all the resources you need. Using CloudFormation, you can set up, configure, and find AWS resources that depend on each other automatically.

CloudFormation's three primary building blocks are stacks, templates, and changesets. A template is a text file that lists the steps and materials needed to start an application.

The activation of an AWS template starts CloudFormation, which finds and sets up the required account resources, data flows, and dependencies.

Benefits of AWS CloudFormation

AWS CloudFormation offers a lot of benefits, some of which are listed below:

  • Integration with CI Pipeline

    "CI" stands for "continuous integration." You can attach your YAML or JSON template files to services such as GitHub Hooks.

    Then, when you change your files, the template will automatically start a pipeline in AWS through the code pipeline and use CloudFormation to deploy all of your changes. Therefore, setting up an entire CI pipeline for your infrastructure changes is simple.

  • Automate & Deploy

    AWS CloudFormation automates the provisioning of your application's resources. This lets you quickly build and rebuild your apps and infrastructure without scripting or time-consuming manual steps.

    CloudFormation removes manual steps like figuring out what actions to take when maintaining your stack, putting them together in the best way, and reverting changes immediately if an error is found.

  • Easy to Use

    When AWS releases CloudFormation, users will be able to configure environments in which to carry out elaborate procedures.

    CloudFormation can also help you expand into new regions because it makes it easy to send resources to multiple regions simultaneously with just one set of commands.

  • Consistency 

    With AWS CloudFormation templates, you can set up and deploy AWS services with the same configuration every time.

    When you use CloudFormation, you can rest assured that no matter how many instances you spin up, the quality of your apps and services will remain unchanged.

    If each resource was set up individually, the engineer in charge of the job might use different parameters for each instance, leading to inconsistency; maintaining order in your environment would be more difficult, even if all of the resources did the same basic function. 

  • Security

    CloudFormation parameters can be selected through the AWS UI to quickly and easily set up AWS resources. Inadvertently opening up your system to vulnerabilities can happen if you are not careful.

    You will have to put in a lot of effort and money to fix or stop undesirable things from happening.

    The CloudFormation template enables you to create and test code before deploying it. Thus, you can anticipate faults and remove them without delay. Likewise, you'll easily pinpoint which updates brought about particular issues with your AWS assets.

  • Easy Updates 

    With AWS CloudFormation templates, you may deploy new resources and modify existing ones. This quality makes it easier to add more storage to a group's EC2 instances or change their access policies.

  • Infrastructure Modifications for Coding Review

    Your infrastructure update process will be more reliable if you treat your CloudFormation infrastructure as if it were a piece of code and read through it before making any changes.

    Instead of having an uninformed user make changes to the console, changes to the underlying infrastructure can be made with the help of a change management system and code reviews.

Understanding AWS CloudFormation Concepts

CloudFormation templates organize resources, variables, and functions. Thus, it helps to have a firm grasp of these fundamental concepts.


A template is a text file that lists the steps and materials needed to start an application. The activation of an AWS template starts CloudFormation, which finds and sets up the required account resources, data flows, and dependencies.

In CloudFormation, a "template" is a text file in either the JSON or YAML formats. The files can be saved with any extension, including JSON, YAML, template, or txt.

These templates serve as guides for CloudFormation as it creates your AWS infrastructure.

In a template, you can use the instance type, AMI ID, block device mappings, and the associated Amazon EC2 key pair name to describe an Amazon EC2 instance.

When you make a stack, CloudFormation uses the template you provide to make whatever you tell it.


AWS defines a "stack" as a group of related resources (such as EC2 instances, S3 objects, and IAM roles) that can be managed with a single set of configuration settings.

Stacks are collections of resources you can create, modify, and remove. All of a stack's resources are specified in the stack's CloudFormation template. 

For example, you've developed a template that includes an Amazon RDS database instance, an elastic load balancer, and an auto-scaling group.

By sending in your template as part of creating a stack, CloudFormation can automatically give you the resources you need. 

Change Sets

You can update the deployment of any CloudFormation by modifying the original deployment template. If you want to ensure that the changes you want to make to the template are included in the update, you can create a change set.

Using change sets, you can analyze how potential modifications would affect already-running resources, which is very useful when dealing with mission-critical resources.

Changing the name of an Amazon RDS database instance will cause CloudFormation to create a new database and delete the old one. If you have a backup of the old database, you can restore all its data.

With the help of a change set, you can see that your update will result in a database replacement, giving you time to prepare before updating your stack.

AWS CloudFormation Features

AWS CloudFormation simplifies the modeling, quick and consistent provisioning, and lifetime management of a set of interconnected AWS and third-party resources by treating infrastructure as code.

You can launch and configure your stack of resources with a CloudFormation template that details your preferred resources and how they relate to one another.

You can use a template to create, edit, and delete a whole stack of resources at once rather than managing each resource individually. Let’s find out about the main features of AWS CloudFormation.

  1. 1

    Authoring with JSON/YAML

    AWS CloudFormation lets users model their infrastructure while creating documents. Users can express what AWS resources they want to create and configure using open-source languages such as JSON or YAML.

    If a user wants to design visually, he/she can use AWS CloudFormation Designer to get started with an AWS CloudFormation template. 

  2. 2

    Safety Controls

    AWS CloudFormation allows for the automated, governed provisioning and modification of the user's infrastructure. No erroneous inputs from the user's end are required.

    During the stack building and update process, the user can tell CloudFormation which CloudWatch alert to keep an eye on. If any alarms are not met, AWS CloudFormation will undo the entire stack process and return it to a previously deployed state.

  3. 3


    With AWS Lambda and CloudFormation, users can add their functionality to the predefined user stack template.

    Users can take advantage of Custom Resources, an extensibility method that lets them create their provisioning code in a Lambda function and have it activated in a CloudFormation stack.

    Users can build their own provisioning logic to set up a resource from a third party or test the most recent AMI IDs for use in user stacks.

  4. 4

    Dependency Management 

    When you use AWS CloudFormation to manage stacks, the dependencies between your resources are taken care of automatically.

    CloudFormation figures out the best way to add, change and remove resources from a stack without you having to tell it exactly what to do.

Working with Stack Sets

With AWS CloudFormation StackSets, you can make stacks much more powerful by creating, updating, or deleting stacks across multiple accounts and AWS Regions with a single operation.

The administrator makes an AWS CloudFormation template and then takes care of it. This template is then used to provision stacks into other accounts in the AWS Regions of the administrator's choosing.

Automating AWS CloudFormation with Code

When deploying your workloads to the Amazon Web Services (AWS) Cloud, using AWS CloudFormation can help you save time both during and after development.

Using templates is a great time-saver and an excellent way to guarantee that your documents won't become outdated. Here, we'll go over some best practices for AWS customers and AWS Partners to follow when using AWS CloudFormation to build infrastructure as code. 

  • Use pre existing AWS CloudFormation templates as a starting point

  • Construct reusable, modular templates

  • Use existing repositories as submodules

  • Take advantage of a linting integrated development environment

  • Set up paths to your external resources by using parameters.

  • Use the same names for common parameters

  • Using TaskCat, you can automate your AWS CloudFormation testing

  • Maintain your templates

Deploying Applications with AWS CloudFormation

AWS CloudFormation allows applications to be deployed to Amazon EC2 instances with minimal human intervention.

You can save a lot of time and effort by using this method to create copies of deployments and apply updates to existing installations without having to connect directly to the instance.

CloudFormation comes with a collection of cloud-init-derived helper scripts like cfn-init, cfn-signal, cfn-get-metadata, and cfn-hup. CloudFormation templates can use these helper scripts to more easily deploy, configure, and update applications running on Amazon EC2 instances.

Best Practices for Using AWS CloudFormation

The following are the best practices for using AWS CloudFormation:

  • Reduce Feedback to Speed Delivery

    Use the AWS CloudFormation template's methods and resources to cut down on infrastructure feedback loops. Before committing your templates to a source code repository, you should lint and test them locally to ensure they are free of syntax and configuration errors.

    Early detection is crucial for avoiding problems in later stages of the life cycle, such as the development, quality assurance, and production phases. Early testing and fail-fast reduce rework wait time, potential impact, and confidence in provisioning operations.

  • Organize Stacks by Lifecycle and Ownership

    Determine the stack's contents based on the ownership and current state of AWS resources. Keeping track of one single stack can become challenging and time-consuming as your stack grows.

    By aggregating resources with similar lifecycles and ownership, owners can change their set of resources through their own process and schedule.

  • Export Shared Resources Using Cross-Stack References

    When organizing AWS resources by lifecycle and ownership, you should build a stack that uses resources from another stack. Hardcode resource names and IDs or use input parameters.

    These methods can make templates hard to reuse or increase stack startup overhead. Instead, export stack resources using cross-stack references. Through the Fn::ImportValue function, stacks gain access to the exported resources.

  • Check All Resource Quotas

    Check your AWS account limits before launching a stack. AWS CloudFormation will only create your stack once you increase your quota or delete resources. You should know each service's limits before launching a stack.

  • Modularize Resource Configurations

    If your infrastructure is expanding, you may find yourself declaring the same components across multiple templates.

    Modules make it possible for stack templates to have their resource configurations packaged in a way that is visible, manageable, and repeatable. Stack templates use modules to encapsulate standard service configurations and best practices.

  • Deploy Software on Amazon EC2 Instances with AWS::CloudFormation::Init.

    Using the CFN-init helper script and the AWS::CloudFormation::Init resource, stacks can install and configure software on Amazon EC2 instances.

    Instead of procedural scripting steps, AWS::CloudFormation::Init lets you describe configurations. Update configurations without recreating instances. AWS CloudFormation generates logs for troubleshooting configuration issues.

  • Update Your Amazon EC2 Instances 

    CloudFormation Linux and Windows instances should periodically execute yum update to ensure they have installed the most up-to-date RPM package. By doing so, you can rest assured that you are always using the most up-to-date version.

Troubleshooting AWS CloudFormation

Have you ever encountered AWS CloudFormation errors that have tripped up the final stage of the development process? If so, then you’re not alone. Let’s find out how you can troubleshoot common errors of AWS CloudFormation.

Syntax & Semantic Errors

The most common errors using AWS CloudFormation are Syntax and Semantic. Such errors are the result of using JSON or YAML templates. Uploading CloudFormation usually highlights issues like missing brackets or indents. 

The fix for this is easy: just look at the wrong line and fix the syntax or format.

After staring at the screen for hours, it can be hard to see, but the AWS console lets you know if there is a minor error like this and gives you a line number to help you find it.

If that line doesn't have an error, it may be above it. VSCode's code-highlighting feature is another option. 

Dependency Errors

When you develop complex architectures, you can face a situation where, in your stack, your resources must be created in a particular order. 

You can resolve errors caused by missing dependencies by adding DependsOn attributes to template resources that rely on other resources.

Sometimes, you have to tell AWS CloudFormation about dependencies so that it can create or delete resources in the right order. 

Insufficient Permissions Errors

Sometimes, you can forget minor permission requirements when you think a particular thing is easy. The same is true for configuring your resources via YAML files.

Due to requirements, sometimes your resources have to interact with each other, which requires permission. 

You can easily correct such an error by granting all required permissions to your resources.

When troubleshooting such errors, start with admin and work down to the necessary permissions. That way, you won’t get blocked during the development process. 

Missing Required Properties Errors

AWS CloudFormation stacks often fail due to invalid input parameters, unsupported resource property names or values, or both. Make sure the resource exists before proceeding with the input. AWS-specific parameter types enforce correct values.

Use valid resource property names and values in your template. For a complete list of resources and property names, see the AWS resource and property types reference.

No Update to Perform Errors

AWS CloudFormation stack updates require template or parameter changes.

Changes to the template's deletion policy, update policy, condition declaration, or output declaration will not be picked up by AWS CloudFormation. Adding or removing an attribute won't affect other parts of a resource's metadata.


Why would you use AWS CloudFormation?

Abstracting resource APIs simplifies declarative deployment and updating of compute, database, and other resources.

With AWS CloudFormation, you can manage resources across accounts and regions and implement automated rollbacks and state management.

What is AWS CloudFormation stack?

AWS CloudFormation stack is a collection of AWS resources that are created using a template and can be managed as a whole.

Is CloudFormation CI CD?

Yes, CloudFormation is CI/CD. AWS CloudPipeline is a framework for continuous integration and CI/CD that lets developers update code in a safe way. 


Time is money! Your team is wasting time if they have to set up and deploy AWS resources manually. This configuration increases the likelihood that something will be missed or done incorrectly, leading to management issues and security vulnerabilities.

This also slows down the process of making changes or expanding the available resources.

Your team can make the AWS deployment process more efficient and straightforward with IaC instruments like CloudFormation. That is to say, you can deploy as many new instances as you like, and your resources will only need to be configured once.

With AWS CloudFormation templates, you can easily monitor the state of your infrastructure and make changes with confidence over time.

About the author


Youssef is a Senior Cloud Consultant & Founder of

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