Using Kubernetes labels for cost allocation in EKS

Split cost allocation data supports Kubernetes labels as cost allocation tags for Amazon EKS clusters. While these labels are automatically imported as user-defined cost allocation tags, they require activation at the management account level. Once activated, you can use them to attribute pod-level costs in your Cost and Usage Reports (CUR) using custom attributes such as cost center, application, business unit, and environment.

This feature helps organizations accurately track and allocate costs in shared EKS environments across teams, projects, or departments. Using Kubernetes labels, you can allocate your Kubernetes costs based on your specific business requirements and organizational design.

Prerequisites

As prerequisites for using Kubernetes labels with split cost allocation data:

• You need to enable split cost allocation data in the AWS Billing and Cost Management console. This must be enabled at the management account level. For details, see Enabling split cost allocation data.

• You need an EKS cluster for which you want to track split cost allocation data. This can be an existing cluster, or you can create a new one. For more information, see Create an Amazon EKS cluster in the Amazon EKS User Guide.

• You must have labels assigned to your pods in the EKS cluster. For more information on how to create labels in Kubernetes, see Labels and Selectors in the Kubernetes Documentation.

Working with Kubernetes labels in EKS

Split cost allocation data supports up to 50 Kubernetes labels per pod, which are sorted alphabetically before being imported as cost allocation tags. Any labels beyond the first 50 are automatically discarded. If you need to add a new cost allocation tag after reaching the 50-label limit, you must first remove an existing label and ensure your new label falls within the first 50 when alphabetically sorted.

Note

Some AWS managed services automatically add labels to EKS pods. These labels count toward the 50-label limit per pod and will appear on your cost allocation tags page.

While Kubernetes labels have no size restrictions, cost allocation tags have specific character limits: 128 characters for tag keys and 256 characters for tag values. Labels that exceed these character limits will be discarded and not presented as cost allocation tags. It's recommended to create labels that follow these character limits for cost allocation purposes.

The imported Kubernetes labels appear as cost allocation tags and must be activated at the payer account level. For more information on cost allocation tags and activation, see Using user-defined cost allocation tags. The following cost allocation tag limits apply: 50 user-defined tags per resource and 500 user-defined tags per payer account. System-generated tags do not count toward these limits.

Note

After you create and apply user-defined tags to your resources, it can take up to 24 hours for the tag keys to appear on your cost allocation tags page. Once you activate the tags, it can take an additional 24 hours for them to become active.

Managing Kubernetes labels and cost allocation tags

You can add, delete, and edit Kubernetes labels in EKS, as well as deactivate the associated cost allocation tags. The following describes the expected behavior for each action.

Adding a new label

You can add a new Kubernetes label to a pod. If the label limit of 50 has not been reached, the new label will be imported and offered as a cost allocation tag, which can then be activated. However, if the limit of 50 has been reached, the new label will not be imported even if it falls within the alphabetical sort order of first 50 labels. You must first deactivate an existing cost allocation tag to import a new label.

Editing a label

Kubernetes does not allow you to edit a label key. To change a label key, you must remove it and add a new label. However, you can edit label values, which will be reflected in your next CUR.

Deleting a label

You can remove a label from EKS pods. Note that removing a label does not automatically deactivate its associated cost allocation tag. Split cost allocation data will continue to populate in CUR until you explicitly deactivate the cost allocation tag.

Deactivating a cost allocation tag

You can deactivate any cost allocation tag created from Kubernetes labels. Once deactivated, data will no longer populate in the respective columns, and the column will be deleted from the next month’s CUR.

Best practices for managing Kubernetes labels for cost allocation

Kubernetes labels provide significant flexibility in shared cost allocation modeling. To maximize the potential of this capability, we recommend following these best practices to optimize your cost management approach.

Understanding label limits

The 50-label-per-pod limit is based on alphabetical sorting. Only the first 50 alphabetically ordered labels will be imported for cost allocation. To ensure critical labels are included, carefully plan your label naming to ensure important labels appear within the first 50 when alphabetically sorted.

Following character constraints

AWS cost allocation tags have the following character limits:

• Tag keys: 128 characters

• Tag values: 256 characters

While Kubernetes allows longer labels, any labels exceeding these limits will not be imported. Design your labels within these limits to ensure successful cost allocation tracking.

Adding new labels when at capacity

When a pod has reached the 50-label limit and you need to add a new cost allocation label, follow these steps:

1. Review existing labels and identify a cost allocation tag to deactivate.

2. Deactivate the selected tag.

3. Add the new cost allocation label.

4. Verify the new label falls within the first 50 alphabetically sorted labels.

Note

Remember that only the first 50 alphabetically sorted labels are used for cost allocation.