Template structure (JSON/YAML) in AWS - Step-by-Step Execution

Process Flow - Template structure (JSON/YAML)

Start Template

↓

Version

↓

Declare Parameters

↓

Define Resources

↓

Set Outputs

↓

End Template

This flow shows the main parts of an AWS CloudFormation template from start to finish.

Execution Sample

AWS

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Parameters": {},
  "Resources": {},
  "Outputs": {}
}

A minimal AWS CloudFormation template structure in JSON format.

Process Table

Step	Section	Action	Details	Result
1	Start Template	Begin parsing	Recognize template start	Template parsing started
2	Version	Read AWSTemplateFormatVersion	Version set to 2010-09-09	Version recorded
3	Parameters	Check for parameters	None defined here	No parameters to process
4	Resources	Check for resources	None defined here	No resources to create
5	Outputs	Check for outputs	None defined here	No outputs to return
6	End Template	Finish parsing	Template fully parsed	Template ready for deployment

💡 Template parsing ends after reading all main sections.

Status Tracker

Variable	Start	After Version	After Parameters	After Resources	After Outputs	Final
AWSTemplateFormatVersion	undefined	2010-09-09	2010-09-09	2010-09-09	2010-09-09	2010-09-09
Parameters	undefined	undefined	{}	{}	{}	{}
Resources	undefined	undefined	undefined	{}	{}	{}
Outputs	undefined	undefined	undefined	undefined	{}	{}

Key Moments - 3 Insights

Why do we need the AWSTemplateFormatVersion section?

It tells AWS which version of the template format you are using, ensuring compatibility. See execution_table step 2.

What happens if no Resources are defined?

No AWS resources will be created or changed. The template is valid but does nothing. See execution_table step 4.

Can Outputs be empty?

Yes, Outputs are optional and can be empty if you don't need to return any information after deployment. See execution_table step 5.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result after reading the Parameters section?

A Parameters are undefined

B Parameters contain resource definitions

C Parameters are set to an empty object {}

D Parameters cause an error

💡 Hint

Check execution_table row 3 under Result column.

At which step does the template parsing finish?

A Step 5

B Step 6

C Step 4

D Step 2

💡 Hint

Look at the last row in execution_table for the End Template step.

If you add a resource to the Resources section, which variable changes in variable_tracker?

A Resources

B Parameters

C AWSTemplateFormatVersion

D Outputs

💡 Hint

Resources variable changes after the Resources section is processed.

Concept Snapshot

AWS CloudFormation template structure:
- Start with AWSTemplateFormatVersion
- Define Parameters (optional inputs)
- Define Resources (AWS services to create)
- Define Outputs (optional results)
Each section is a JSON/YAML key
Templates must be valid JSON or YAML

Full Transcript

An AWS CloudFormation template is a text file in JSON or YAML format. It starts with a version declaration called AWSTemplateFormatVersion. Then it can have Parameters to accept inputs, Resources to define AWS services to create, and Outputs to return information after deployment. The template is read from top to bottom. If any section is missing, it is treated as empty. The template must be valid JSON or YAML to deploy successfully.