Reallocation Rules Best Practices and Common Pitfalls

Products

• CloudHealth

Issue/Introduction

This article provides an overview of the Reallocation Rules and highlights some of the main areas that commonly come up in tickets.

Resolution

Why use reallocation rules?

Organizations often look at cost broken out by perspectives.  The challenge is that not all costs can not be allocated directly with a perspective.  This type of cost is referred to as “indirect cost”.  Reallocation rules allow indirect costs to be reassigned to perspective groups based on specific criteria.

 

Best Practices when Creating Reallocation Rules

The first step is to determine why you are setting up the reallocation rule and how you would like to see it represented.  The explanation should include three key parts:

1. What are you trying to reallocate?
2. Does the cost need to move across accounts, or should it remain in the same AWS account and it just needs to move perspective groups?
3. What should determine where the cost ends up?
   • Which perspective serves as a basis for how you want the cost reallocated?
   • Do you want the reallocation proportional to other costs? Or do you want to specify how much each group gets?
   • Which perspectives are used for financial reporting? Do you use all or only a subset for financial reporting? → In other words, does this perspective get used on the Cost History report?  If no, then it does not need to be included in the reallocation rule
   • Do you want the reallocation proportional to other costs or do you want to specify how much each group gets?
     • If “Reallocate Across Accounts” = Yes:
     • If “Reallocate Across Accounts” = No:  

Be advised that some charges may not reside in a single group inherently.  "AWS Support", for instance, is not associated to a region so it would split the cost evenly across all groups.

 

Example 1: Support cost is billed in a single line item to the consolidated account.  You want to spread this cost out to the linked accounts proportional to the accounts total usage.

1. What are you trying to reallocate?     “Reallocate From” = Enterprise Support
2. Does the cost need to move across accounts or should it remain in the same AWS account and it just needs to move perspective groups?    “Reallocate Across Accounts” = Yes
3. What should determine where the cost ends up?
   1. Which perspective servers as a basis for how you want the cost reallocated?    “Relocate to” = Budget Perspective
   2. Do you want the reallocation proportional to other costs? Or do you want to specify how much each group gets?    Proportional to list of direct costs

 

Example 2: All of your EBS snapshots cost is showing in Assets Not Allocated.  You want to have this cost show in perspective groups proportional to their EBS storage cost. The cost should move into groups but stay in the same account.

1. What are we trying to reallocate?    “Reallocate From” = EBS Snapshot
2. Does the cost need to move across accounts or should it remain in the same AWS account and it just needs to move perspective groups?    “Reallocate Across Accounts” = No
3. What should determine where the cost ends up?
   1. Which perspectives are used for financial reporting?    “Relocate to” = Budget Perspective, Cost Center, Environment
   2. Do you want the reallocation proportional to other costs?  Or do you want to specify how much each group gets?    Proportional to EBS Storage

Across Account vs. By Account?

When Reallocation Across Account is enabled, the reallocation allocation process changes the actual underlying cost.  This means that the results of the reallocation rule will be visible even when you are not viewing the history cost report by the target Perspective.  For this reason, you are allowed to select only one perspective to relocate to which serves.

 

Understanding Reallocation Rule Results

In the Cost History report, there is an available y-axis measure called “Cost before Reallocation (Original) ($)”.  You can use this compared to the default “Cost ($)” to understand how the reallocation rules moved cost.

 

Processing

• Reallocation rules are applied as part of nightly processing starting at 8pm EST.  Any new rules or updates to existing rules will be applied during the next processing and so can take up to 24 hours to show in reports.

• Reallocation rules are applied to all months including historical months.