In recent years, workload deployments have been increasingly shifting to cloud automation services to help with the seamless transitioning of business processes. Amazon Web Services (AWS) CloudFormation is one such service that allows users to customize their own AWS setup for AWS resources.
AWS CloudFormation ensures that you spend less time on managing resources and devote more time to focusing on applications that use AWS. It is as simple as creating a template for the AWS resources so that CloudFormation can automatically provision and configure the resources on behalf of the user.
Users usually have to create individual AWS resources and configure them manually. But if you use AWS CloudFormation, you can automate and handled it without any manual intervention. But these templates can sometimes become obsolete after development or even during development due to regular updates.
That said, you can resort to some best practices so that the templates are usable for a long time, and this is what this informative guide is all about!
8 Best Practices For AWS CloudFormation
Here are eight practices you should adopt for AWS CloudFormation:
#1 Use AWS CloudFormation Templates Initially
When using AWS CloudFormation for infrastructure as code, check if the resource already exists. Often, the resource may have already been created and shared within the community. You can search for complete solutions and individual aspects of them.
You can start by looking at the AWS Quick Starts, accessible on GitHub and open-source. So, it is free and easily accessible. Search on the homepage using keywords, partners, products, or filter by common use cases on the AWS Quick Starts.
You can also check AWS Labs, an open-source platform available on GitHub with numerous AWS CloudFormation templates. These templates are formulated by AWS and a group of AWS customers and partners.
Using an automated deployment that uses standard AWS resources and pre-made templates will significantly reduce the effort you otherwise would have to put in.
#2 Use Smaller Templates
Indeed, you can use one AWS CloudFormation template, but making smaller templates can also prove to be fruitful. For example, making one AWS CloudFormation template will prove very difficult and complex if you have a 3-tier application.
In addition, it would be very cumbersome to troubleshoot if any issue arises. But the troubleshooting and setup would become considerably more manageable if you had smaller templates for each function. So you can have smaller children templates for each of the layers and then a parent layer that would deploy each of the children layers in sequence.
If you use this, your work will become much simpler. Also, you can later export the smaller templates for use in other web applications.
#3 Organize Stacks Based On Ownership And Lifecycle
You can put all your resources in one stack if you are just starting out. But as your application grows and your development scales, you will eventually have numerous resources, demanding different stacks for storage.
When stacking such resources, organize them according to their lifecycles and ownership. Their process and schedule can change each set of resources without interfering in any other stacks at any point.
Once the AWS resources are organized in stacks, you can build a separate stack that draws resources from another stack. You can use the traditional hardcoding values and input parameters to allow sharing resources within the templates using resource names and IDs.
However, this renders the templates unusable for the future or increases the overhead costs required to re-initiate the stack. So, it’s best to use a cross-stack reference to export the resources from one stack to another that may need it.
#4 Use Submodules
There are existing repositories that consist of numerous submodules that have already been created. Using these submodules can prove to be very fruitful and help save time and money.
You save time in the development process and do away with the obligation to maintain unnecessary resources. Suppose you are using a GitHub Repository to deploy your AWS CloudFormation. In that case, you can directly import the GitHub submodules to the parent AWS template — click on the ‘Github submodule add’ option.
For example, the Amazon Virtual Private Cloud QuickStart: if you need to deploy new infrastructure, you can use the QuickStart VPC as a submodule in your repository. You can direct it to the GitHub account or clone it into your AWS Quickstart account. Next, you can use this submodule as a child stack, and the parent stack can pass on the parameters required to describe the VPC.
#5 Reuse Templates For Replicating Stacks
When you have your stacks and resources set up, you can replicate the templates for use in other environments. You can make different development, testing, and production environments and test the templates to make changes before implementation.
To ensure you can use the templates again, use the mappings, conditions, and parameters section to customize the stacks when you create them. For example, when testing the development environment, you can set a low-cost parameter different from the production environment, whereas all other parameters would remain the same.
In addition, when reusing the template, check the kind of inputs required. If the input needed is for AWS-specific values like Amazon EC2 key pair name or Amazon Virtual Private Cloud IDs, use AWS-specific parameter types.
AWS ClodFormation can quickly validate AWS-specific parameter types. In addition, the CloudFormation console provides a drop-down list of all VPC IDs and key pair names, so you do not need to memorize them.
#6 Common Parameters Should Have Similar Names
Using the approach stated above, where you use multiple smaller templates for individual functions, you would soon have to work with numerous templates.
For instance, the Amazon EKS QuickStart consists of 15 templates. Outputs are transported from a selected template to another in the infrastructure as parameter values. But if the parameter names are kept constant in all AWS CloudFormatioon templates, it would not be difficult to keep track of all the parameters. It would also be much more convenient to troubleshoot and reiterate.
For example, consider the parameter VPCID of the QuickStart deployment and deploy it as a submodule. The assets would be deployed to a new VPC using the output ‘VPCID.’ This output would be used to deploy it as a parameter value from the submodule to other templates. Naming the parameter as VPCID in all the templates would simplify tracking it if required at any point.
#7 Use TaskCat To Automate AWS CloudFormation
After making an AWS CloudFormation template, it’s crucial to test it. The testing usually involves uploading the template to an S3 bucket, signing into AWS management Console, opening the AWS CloudFormation console, in the parent template using the S3 path to enter and input the parameter values manually, launching the stack and waiting to see whether the deployment works.
This process is time-consuming, especially if it has to be done across numerous AWS regions and cleaned up. Also, you may fail to track assets that you tested or deployed. When you forget, you may leave assets during the clean-up. These assets can completely alter the AWS billing statement with unforeseen charges.
As mentioned above, the AWS Quick Start team created TaskCat, an open-source tool. TaskCat automates the testing process for the AWS CloudFormation. It automatically logs the deployment results once the test is initiated in a Region and deletes the assets after the testing is completed.
This ensures that you do not have to spend enormous time ensuring that testing was done correctly or worry about leaving assets after testing.
#8 Maintain The Templates
Did you know that you can use the AWS CloudFormation templates for automation? This means that you can use them for years on end. They may lose their general availability or completely outdate. So, you must regularly test the templates while integrating new service functionalities. This will help you to use the template for a long time.
By adhering to the tips mentioned above, you will keep your AWS CloudFormation templates well maintained for a good amount of time. Just make sure you use the right processes and parameters for automation and keep the templates updated.
Can Individual AWS Resources Be Managed As Part Of An Aws CloudFormation Stack?
Yes! The user controls all elements present in an infrastructure and can use all AWS and third-party tools to maintain the AWS resources. However, since CloudFormation has certain best practices, additional rules, and compliance controls, it is recommended that you allow CloudFormation to control the resource changes.
What To Do If You Cannot Name All Resources?
You can easily rename some resources like the Amazon S3 buckets, thanks to CloudFormation. But you cannot rename specific resources so that no issues arise when updates occur and the resource is replaced. Also, renaming every resource limits the reusability of a template, such that you cannot name every resource.