Templates

Overview

Templates live in the templates/ directory. Rain deploys each file as a separate CloudFormation stack, matching it with environment-specific parameters from parameters/<env>/.

Location and format

Store every template under templates/. Both YAML (.yml or .yaml) and JSON formats are supported.

Rain deploys each file individually, so keep tightly related resources together in one template to minimize the number of stacks you manage.

Naming conventions

Convention	Description
File naming	Use lowercase, hyphen-separated names (e.g., `network.yml`, `oidc-provider.yml`)
Stack names	Override with `StackName` in parameter files for multi-environment usage
Parameter pairing	Match template and parameter file names exactly; deploy script auto-discovers configuration

Rain deployment behavior

During deployment, the script executes:

rain deploy "<template>" --yes --config "<parameters>"

Flag	Purpose
`--yes`	Skips interactive prompts so CI/CD stays non-blocking
`--config`	Loads parameters and tags from the environment folder

If no matching parameter file exists, Rain deploys the template with defaults.

To experiment with change sets or additional flags, run Rain directly or modify the deploy script.

For a step-by-step walkthrough, read our guide on deploying a CloudFormation template.

Adding templates

Add new files to ./templates and commit to the main branch. The CI/CD workflow automatically deploys new stacks using the provided parameter files.

Template resources:

Best practices

Practice	Description
Use Transform section	Leverage Transform for macro libraries like AWS SAM
Add Metadata blocks	Document why resources exist and which team owns them
Keep idempotent	Avoid `Custom::` resources with destructive operations unless they handle retries cleanly
Use consistent tagging	Apply tags via parameter files for cost allocation and organization

Next steps

Parameters reference - Configuration file structure
Rain reference - Deployment CLI details
Scripts reference - Helper automation