AWS CloudFormation Conditions Overview
- Purpose of Conditions: Conditions in AWS CloudFormation templates allow you to specify that certain resources are created or certain outputs are declared only when certain conditions are met.
- Use Cases:
- Environment-specific resources: Create resources only in dev, test, or prod environments.
- Region-specific resources: Conditionally create resources based on the AWS region.
- Parameter-based conditions: Create resources based on specific parameter values.
- Referencing in Conditions:
- Conditions can reference other conditions.
- Conditions can reference parameter values or mappings.
Defining Conditions
- Syntax: Conditions are defined using intrinsic functions such as
And, Equals, If, Not, and Or.
- Example:
- Define a condition named
CreateProdResources.
- Check if the
EnvironmentType parameter is equal to prod.
- If
EnvironmentType is prod, the condition evaluates to true.

Using Conditions in Templates
- Application: Conditions can be applied to resources, outputs, etc.
- Example:
- An EC2
VolumeAttachment named MountPoint has a condition CreateProdResources.
- If
CreateProdResources is true, MountPoint is created.
- If false,
MountPoint is not created.

Exam Tips
- Writing Conditions: Knowing how to write conditions is not required for the exam.
- Understanding Conditions: Be aware that conditions exist and can be used to control resource creation and outputs.
Conclusion
- Conditions are a powerful feature in AWS CloudFormation that provide flexibility in template deployment.
- They are particularly useful for managing environment-specific configurations within a single template.
- While detailed knowledge of writing conditions is not necessary for the exam, understanding their purpose and use is important.