The CloudFormation registry acts as a repository where you can register and manage modules for use within your AWS account and Region. You can register modules from various sources, including AWS, third-party publishers, and your own custom extensions, within your account and Region. For more information, see Managing extensions with the CloudFormation registry.
Modules can have different versions, so you can specify which version of a module you want to use. This versioning capability is particularly useful when you need to update or modify a module without breaking existing stacks that depend on it.
Keep in mind the following considerations when using multiple versions of a module:
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During stack operations, CloudFormation uses whatever version of the module that's currently registered as the default version in the AWS account and Region in which the stack operation is being performed. This includes modules that are nested in other modules.
Therefore, be aware that if you have different versions of the same module registered as the default version in different accounts or Regions, using the same template may result in different results.
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During stack operations, CloudFormation uses whatever version of the resource that's currently registered as the default version in the AWS account and Region in which the stack operation is being performed. This includes the resources generated by including modules.
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Changing the default version of a module doesn't initiate any stack update operation. However, the next time you perform a stack operation with any template containing that module, such as a stack update, CloudFormation will use the new default version in the operation.
The one exception to this is performing a stack update with the use previous template option specified, as described below.
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For stack update operations, if you specify the use previous template option, CloudFormation uses the previous processed template for the stack update, and doesn't reprocess the module for any changes you might have made to it.
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To guarantee uniform results, if you are including modules in a stack template for use with stack sets, you should ensure that the same version of the module is set as the default version in all the accounts and Regions in which you are planning to deploy your stack instances. This includes for modules that are nested in other modules. For more information, see Managing stacks across accounts and Regions with StackSets.
Requirements for activating third-party public
modules
To successfully activate a third-party public module in your account and Region, the following must be true for each third-party public extension (resource or module) included in the module:
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Extension activation – The extension must be activated in the account and Region you want to use it in. For more information, see Use third-party public extensions from the CloudFormation registry.
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Alias registration – If the extension in the module uses a type name alias, the extension must be registered in your account and Region using the same type name alias. For more information, see Use aliases to refer to extensions.
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Version compatibility – The extension version currently activated must be one of the supported major versions of that extension specified in the module.
If you do not have the correct third-party public extensions and extension versions activated, CloudFormation will fail the operation with an error listing the extensions and versions that need to be activated before the module can be successfully activated.
