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In this lesson you’ll learn how to add Metadata to a CloudFormation template resource and how it differs from Tags. Metadata provides contextual, human- or tool-readable information about resources in your template — useful for ownership, lifecycle tracking, and template versioning. Metadata does not directly change how CloudFormation creates or manages resources, but external tooling and CloudFormation helper scripts can read it to perform additional actions (for example, configuring instances with cfn-init). Where to declare Metadata Metadata is declared under a resource at the same indentation level as Type and Properties. The following example shows an AWS::S3::Bucket resource that includes a Metadata block: 
Resources:
  MyS3Bucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: eden-kodekloud-xcvt-bkt
    Metadata:
      Purpose: "Creating an S3 bucket"
      Reviewed: "2025-02-07"
      Owner: "John Doe"
      Contact: "johndoe@mail.com"
Common metadata entries:
  • Purpose: short description of why this resource exists.
  • Reviewed: date the template or resource was last reviewed (use ISO format YYYY-MM-DD).
  • Owner / Contact: person or team responsible for the resource.
Metadata entries are arbitrary key/value pairs defined by you. They are stored in the template and do not, by themselves, change how CloudFormation creates or manages resources; tools or helper scripts (for example, cfn-init) can read metadata to affect instance configuration.
Updating the stack with the modified template After saving your template (for example, s3-bucket.yaml), update the CloudFormation stack using the console or CLI. In the console the flow looks like this:
  1. In the CloudFormation console, select the stack you want to update and choose Update stack.
  2. Choose Replace current template (Direct update) and upload your edited template file (Choose file).
  3. Continue through the update steps. If your stack has no parameters, you can skip parameter changes.
  4. Optionally review or edit Tags on the stack (Tags are different from Metadata — see the comparison table below).
  5. Submit the update and monitor the stack Events for progress.
A screenshot of a Windows file-open dialog open to Desktop\cf-project showing a YAML file named "s3-bucket", overlaid on the AWS CloudFormation web console. The dialog shows navigation items (Desktop, Downloads, Documents, Pictures) and file details like date modified and type.
Review and verify the template in the console During the update process, the Review step displays the template source (either a Template URL or the uploaded file) and the usual review pane before you submit. Once the update completes, open the stack’s Template tab to confirm the Metadata block is present — the metadata you included remains in the template and is visible to anyone who inspects the stack.
A screenshot of the AWS CloudFormation console showing the "Review DemoStack" page. It displays Step 1: Specify template with a Template URL (an S3 YAML file) and a left-side progress pane listing the update steps.
Metadata vs Tags — quick comparison
ResourcePurposeVisibility / Use
MetadataFree-form, template-level key/value pairs for humans and tooling (e.g., owner, review date, purpose)Stored in the template; readable by tooling and anyone viewing the template; does not affect AWS resource behavior
TagsStructured key/value pairs recognized by AWS services (e.g., for cost allocation, IAM policies, resource grouping)Applied to resources and used by AWS services (billing, access control, resource organization)
Best practices
  • Use Metadata for template bookkeeping: ownership, review dates, build/configuration hints for tools.
  • Use Tags for operational grouping and billing — Tags are recognized by AWS services.
  • Keep metadata keys consistent across templates to enable automated tooling and searches.
Links and references

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