Check AWS cost allocation tag coverage correctly

Why this is worth a look

AWS cost allocation tags must be activated in Billing and Cost Management before they appear on billing reports, and activation applies to every value sharing that key. The management account or a standalone account outside an organization controls activation. New keys can take up to 24 hours to appear for activation, followed by up to 24 hours to activate. Management account users can backfill up to 12 months, but a resource must have carried the tag historically. In the older CUR schema, resource tag columns include names such as resourceTags/user:owner. CUR 2.0 provides a tags map whose enabled keys appear only when a value applies to the line item.

Read-only Athena query for a CUR 2.0 table created through AWS Data Exports with the tags column selected. It counts billed line items by whether a chosen resource tag key is present.

WITH tag_presence AS (
  SELECT
    CASE
      WHEN tags['resourceTags/CostCenter'] IS NULL THEN 'missing_or_not_applicable'
      ELSE 'present'
    END AS tag_status
  FROM cur_database.cur_table
)
SELECT
  tag_status,
  COUNT(*) AS line_item_count
FROM tag_presence
GROUP BY tag_status
ORDER BY line_item_count DESC;

How to confirm it

1. 01

   Confirm who can activate

   Open Billing and Cost Management in the management account, or in a standalone account that is not a member of an organization. Organization member accounts do not have access to the cost allocation tags manager.

2. 02

   Check the tag key status

   Go to Cost allocation tags and confirm the key is activated. AWS activates the key, so the status applies to all values that share that key. After a tag is created and applied, allow up to 24 hours for it to appear for activation and up to 24 more hours to activate.

3. 03

   Review historical coverage

   If you need past months, use Backfill tags from the management account. Backfill can cover up to the prior 12 months, but values are available only for periods when the resource had that tag assigned.

4. 04

   Run the coverage count

   Use the query against a CUR 2.0 table created through AWS Data Exports with the tags column selected. Replace the database, table, and example key, then read missing_or_not_applicable as an absence from that line item, not automatic proof of a resource-tagging failure.

Primary sources