[CCI-1818] Add documentation for CCM EBS shared cost allocation

content/en/cloud_cost_management/container_cost_allocation.md

@@ -20,6 +20,8 @@ Datadog Cloud Cost Management (CCM) automatically allocates EC2 compute cost in
 
 {{< img src="cloud_cost/container_cost_allocation/cost_allocation_table.png" alt="Cloud cost allocation table showing requests and idle costs over the past week" style="width:100%;" >}}
 
+Additionally, CCM allocates the cost of non-local EBS Volumes used as Persistent Volumes in Kubernetes to individual pods that claim those volumes.
+
 ## Prerequisites
 
 1. Set up and configure [AWS Cloud Cost integration][1].
@@ -30,16 +32,27 @@ Datadog Cloud Cost Management (CCM) automatically allocates EC2 compute cost in
 
 ## Cost allocation
 
-Cost allocation divides EC2 compute costs in the [Cost and Usage Report][4] (CUR) into individual costs for each pod or task running on the instance. These divided costs are then enriched with tags from the nodes, pods, and tasks, which allows you to break down costs by any associated dimensions.
+Cost allocation divides EC2 and EBS volume costs in the [Cost and Usage Report][4] (CUR) into associated individual tasks or pods. These divided costs are then enriched with tags from nodes, pods, tasks, and volumes. This lets you break down costs by any associated dimensions.
+
 
 ### Kubernetes
 
-For Kubernetes allocation, a Kubernetes node is joined with its associated EC2 instance costs. The node's cluster name and all node tags are added to the entire EC2 compute cost for the node. This allows you to associate cluster-level dimensions with the cost of the instance, without considering the pods scheduled to the node.
+#### Compute
+
+For Kubernetes compute allocation, a Kubernetes node is joined with its associated EC2 instance costs. The node's cluster name and all node tags are added to the entire EC2 compute cost for the node. This allows you to associate cluster-level dimensions with the cost of the instance, without considering the pods scheduled to the node.
 
 Next, Datadog looks at all of the pods running on that node for the day. The cost of the node is allocated to the pod based on the resources it has used and the length of time it ran. This calculated cost is enriched with all of the pod's tags.
 
 **Note**: Only _tags_ from pods and nodes are added to cost metrics. To include labels, enable labels as tags for [nodes][7] and [pods][8].
 
+#### Persistent volume storage
+
+For Kubernetes Persistent Volume storage allocation, Persistent Volumes (PV), Persistent Volume Claims (PVC), nodes, and pods are joined with their associated EBS volume costs. All associated PV, PVC, node, and pod tags are added to the EBS volume cost line items.
+
+Next, Datadog looks at all of the pods that claimed the volume on that day. The cost of the volume is allocated to the pod based on the resources it has used and the length of time it ran. These resources
+include the provisioned capacity for Storage, IOPS, and Throughput. This allocated cost is enriched with all of the pod's tags.
+
+
 ### ECS on EC2
 
 For ECS allocation, Datadog determines which tasks ran on each EC2 instance used for ECS. If you enable AWS Split Cost Allocation, the metrics allocate ECS costs by usage instead of reservation, providing more granular detail.
@@ -52,24 +65,33 @@ ECS tasks that run on Fargate are already fully allocated in the CUR. CCM enrich
 
 ### Everything else
 
-Any cost other than EC2, computed for instances hosting Kubernetes pods or ECS tasks, is given the same value and tags as the source metric, `aws.cost.amortized`.
+Cost other than EC2/EBS, computed for instances hosting Kubernetes pods or ECS tasks, is given the same value and tags as the source metric, `aws.cost.amortized`.
+
 
 ## Understanding spend
 
-Using the `allocated_spend_type` tag, you can visualize the spend category associated with your cost at the Kubernetes node, ECS host, or cluster level. Costs are allocated into three spend types:
+Using the `allocated_spend_type` tag, you can visualize the spend category associated with your cost at the Kubernetes node, ECS host, EBS volume, or cluster level. Costs are allocated into three spend types:
+
+### Compute
 
 - Usage: Cost of memory and cpu being used or reserved by workloads.
 - Workload idle: Cost of memory and cpu that is being reserved and allocated but not used by workloads.
 - Cluster idle: Cost of memory and cpu not reserved by workloads in a cluster.
 
+### Persistent volumes
+
+- Usage: Cost of provisioned IOPS, Throughput, or Storage being used by workloads. For Storage, this is based on the maximum amount of volume storage used that day. For IOPS and Throughput, this is based on the average amount used that day.
+- Workload idle: Cost of provisioned IOPS, Throughput, or Storage not being used by workloads. For Storage, this is based on the maximum amount of storage used that day. For IOPS and Throughput, this is based on the average amount used that day.
+- Cluster idle: Cost of provisioned IOPS, Throughput, or Storage for volumes not claimed by any pods that day.
+
 ## Cost metrics
 
 When the prerequisites are met, new AWS cost metrics automatically appear.
 
 | AWS Cost Metric                    | Description    |
 | ---                                | ----------- |
-| `aws.cost.amortized.shared.resources.allocated` | EC2 costs allocated by the CPU & memory used by a pod or ECS task, using a 60:40 split for CPU & memory respectively. <br> *Based on `aws.cost.amortized`* |
-| `aws.cost.net.amortized.shared.resources.allocated` | Net EC2 costs allocated by CPU & memory used by a pod or ECS task, using a 60:40 split for CPU & memory respectively. <br> *Based on `aws.cost.net.amortized`, if available* |
+| `aws.cost.amortized.shared.resources.allocated` | EC2 costs allocated by the CPU & memory used by a pod or ECS task, using a 60:40 split for CPU & memory respectively. Also includes allocated EBS costs. <br> *Based on `aws.cost.amortized`* |
+| `aws.cost.net.amortized.shared.resources.allocated` | Net EC2 costs allocated by CPU & memory used by a pod or ECS task, using a 60:40 split for CPU & memory respectively. Also includes allocated EBS costs. <br> *Based on `aws.cost.net.amortized`, if available* |
 | `aws.cost.amortized.mem.allocated`   | EC2 costs allocated by memory used by a pod or ECS task. <br> *Based on `aws.cost.amortized`* |
 | `aws.cost.net.amortized.mem.allocated` | Net EC2 costs allocated by memory used by a pod or ECS task <br> *Based on `aws.cost.net.amortized`, if available* |
 | `aws.cost.amortized.cpu.allocated` | EC2 costs allocated by CPU used by a pod or ECS task <br> *Based on `aws.cost.amortized`* |
@@ -96,6 +118,7 @@ Datadog consolidates and applies additional tags from various sources to cost me
 | `allocated_resource:cpu`                   | Cost of CPU resources. *Only available for `.shared.resources.allocated` metrics.*                                            |
 | `allocated_resource:memory`                | Cost of Memory resources. *Only available for `.shared.resources.allocated` metrics.*                                         |
 | `allocated_resource:managed_service_fee`   | Cost of cloud provider managed service fees. *Only available for `.shared.resources.allocated` metrics.*           |
+| `allocated_resource:persistent_volume`     | Cost of non-local EBS Volumes used as Persistent Volumes in Kubernetes. *Only available for `.shared.resources.allocated` metrics.*           |
 
 ### Kubernetes
 
@@ -119,6 +142,17 @@ In addition to ECS task tags, the following out-of-the-box tags are applied to c
 | `is_aws_ecs_on_fargate` | All costs associated with running ECS on Fargate. |
 | `is_cluster_idle`       | The cost of unreserved CPU or memory on EC2 instances running ECS tasks. *Only available for `.cpu.allocated` or `.mem.allocated` metrics.*|
 
+### Persistent volumes
+
+In addition to Kubernetes pod and Kubernetes node tags, the following out-of-the-box tags are applied to cost metrics.
+
+| Out-of-the-box tag                      | Description                                                                                                                                 |
+| ---                                     |---------------------------------------------------------------------------------------------------------------------------------------------|
+| `persistent_volume_reclaim_policy`      | The Kubernetes Reclaim Policy on the Persistent Volume.                                                                                     |
+| `storage_class_name`                    | The Kubernetes Storage Class used to instantiate the Persistent Volume.                                                                     |
+| `volume_mode`                           | The Volume Mode of the Persistent Volume.                                                                                                   |
+| `ebs_volume_type`                       | The type of the AWS EBS volume. *Can be `gp3`, `gp2`, and more.*                                                                            |
+
 ## Further reading
 
 {{< partial name="whats-next/whats-next.html" >}}