Implementing Chargeback/Showback for Multi-Tenant Clusters

As organizations embrace multi-tenancy, i.e., sharing clusters among applications/teams to reduce cluster sprawl and spend, it is imperative that granular resource utilization metrics are collected and aggregated from their clusters. Tracking and reporting costs on a per application/team basis (referred to as chargeback/showback) is essential for a number of reasons including:

• Billing internal teams/applications (their cost center IDs) based on their consumption
• Gaining visibility into the cost structure to determine inefficiencies and drive cost optimization exercises
• Forecasting future spend

Rafay's integrated Cost Management solution makes it extremely simple for customers to standardize the collection of metrics in a consistent manner across clusters (cloud, on-premise) and implement chargeback/showback models.

Guide for Success

Step 1: Process/methodology to identify resources belonging to teams/applications

It is important as a first step to put together a process to determine how resources running on a cluster can be identified and mapped to a team/application. Appropriate policies can then be configured to ensure that resources (e.g., namespaces) are always tagged with the right labels.

Important: Rafay's integrated OPA Gatekeeper solution can be leveraged to ensure that resources are deployed with appropriate labels.

Step 2: Apportion costs for Unallocated Resources

There are resources on the cluster that are unused, the costs of which need to be divided among the tenants sharing the cluster. This can be done proportionately (based on tenant usage) or equally among the tenants.

Step 3: Apportion costs for Common Services

There could be services running on the clusters that are "common/shared" to/among the different tenants (teams or applications) using the clusters. Examples include security and monitoring tools. It is important to track the costs for running such services and apportion those appropriately.

Step 4: Consolidation

Some customers also want to take costs for non-K8s resources, personnel, licensing into consideration. This step is to consolidate all those with costs for K8s resources.

Implementing Chargeback/Showback with Rafay

Rafay's integrated cost management solution provides out-of-box options for creating chargeback/showback groups and generating reports.

• Chargeback/showback groups can be a combination of projects, clusters, namespaces, and labels (pod, namespace, etc.)
• Two types of reports can be generated - Summary and Detailed. Summary reports have been tailored for a FinOps type persona and allow aggregation of costs based on Project, Cluster, Namespace, or Application/Namespace labels. Detailed reports are tailored towards identifying inefficiencies and include pod-level metrics aggregated per day.

Important: Rafay's integrated Cost Management solution stores hourly metrics for 2 weeks and metrics on a per-day basis for 6 months.

A typical customer appends appropriate labels to namespaces (e.g., Cost Center ID, BU identifier) and generates summary reports on an ongoing basis to track spend per team/application. Each line item in the generated report will correspond to a "key-value pair" i.e., each Cost Center ID will have a line item.

It is also possible to automate the creation of chargeback groups and generate reports via CLI, API, and TF.

Rafay's cost management solution also provides in-built options to apportion costs for unallocated resources and common services. Costs can be divided based on usage or equally among tenants.

A recent release added the ability to identify common services (e.g., security tools, monitoring tools) through the configuration of namespace list/labels and share the cost of running these common services among tenants (teams/applications) sharing the cluster when generating chargeback/showback reports.

In a subsequent blog post, we will cover how "Cost Explorer" included with Rafay's Cost Management solution can help with "cluster right-sizing" and "application right-sizing" exercises.

Next Steps

If you are interested in learning more about Rafay's "Kubernetes Management" or "Cost Management" offerings,

1. Sign up for a Free Trial
2. Schedule a demo of Rafay Cost Management
3. Reach out if you would like us to create and post videos of specific use cases or scenarios related to Cost Management.
4. Meet us at upcoming events, AWS re:Invent, Gartner IOCS, and several other regional events.