Allocating Shared Costs

Custom Group Dimensions are useful for organizing cloud cost by grouping sets of resources. However, when a resource is shared by multiple systems (customers, products, tenants, etc.), it can be desired to split the cost of that resource between these systems. For example, an RDS database shared by multiple products or teams. This can be accomplished by using Allocation Dimensions.

Allocation Dimensions

An Allocation Dimension is a type of CloudZero Custom Dimension created with the CostFormation definition language. Today there are two types of Allocation Dimensions:

Rules Allocation Dimensions

These dimensions are used to split shared costs across the elements of another dimension. For example, splitting the cost of a shared database among the products using the database, proportional to the products' relative costs. Or, splitting a system-wide operational cost evenly across a number of engineering teams. Rules Allocation Dimensions are a great and easy way to quickly split costs to increase your cloud cost visibility without further engineering work.

Telemetry Allocation Dimensions

These dimensions are used to split shared costs among different target elements based on additional telemetry data provided to the CloudZero platform. Telemetry Allocation Dimensions are a great choice when you need granular control over how the shared costs are split. For example, if you need to split the cost according to a utilization metric.

Use Cases

The next sections go over some common use cases for allocation dimensions.

1. The first splits a shared cost using a proportional rules allocation dimension, which allows us to split the shared cost relative to other costs in another dimension.
2. The second splits a shared cost into new elements using a telemetry stream. This is typical for "cost per customer" or other engineering use cases in which the telemetry represents activity performed by an external user or systems.
3. The third example shows how to combine the split shared cost with an existing dedicated cost. This is common for financial use cases in which the telemetry is a simple (often constant) metric used to distribute the shared cost or when using proportional splits.