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.