A quick reference of common CloudFormation elements

cloudformation-cheatsheet.md

Intrinsic functions

!Ref ResourceName
{ "Fn::Ref": "ResourceName" }

!GetAtt ResourceName.AttributeName
{ "Fn::GetAtt": [ "ResourceName", "AttributeName" ] }

!Sub "something:with:${Variable}"
{ "Fn:Sub": "something:with:${Variable}" }

!Sub
  - something:with:${Variable}
  - { Variable: "foo" }
{ "Fn:Sub": [ "something:with:${Variable}", { "Variable": "foo" } ] }

Syntax

Yaml form	Yaml Shorthand	Original JSON
Fn::Ref arg	!Ref arg	{ "Fn::Ref": arg }

Intrinsic functions can be nested, but take care with the shorthand yaml form as that cannot be nested consecutively.

Ok: Fn::GetAZs: !Ref 'AWS::Region'
Not Ok: !GetAZs !Ref 'AWS::Region'

Global variables

AWS::Region
AWS::AccountId