docs: reserved capacity updates

Author: jmdeal

website/content/en/preview/concepts/nodeclasses.md

@@ -110,6 +110,12 @@ spec:
     # exclusive and can't be specified with other terms.
     # - alias: al2023@v20240703
 
+  # Optional, each term in the array of capacityReservationSelectorTerms is ORed together.
+  capacityReservationSelectorTerms:
+    - tags:
+        karpenter.sh/discovery: ${CLUSTER_NAME}
+    - id: cr-123
+
   # Optional, propagates tags to underlying EC2 resources
   tags:
     team: team-a
@@ -430,7 +436,7 @@ spec:
 ### AL2
 
 {{% alert title="AL2 support dropped at Kubernetes 1.33" color="warning" %}}
-Kubernetes version 1.32 is the last version for which Amazon EKS will release Amazon Linux 2 (AL2) AMIs. 
+Kubernetes version 1.32 is the last version for which Amazon EKS will release Amazon Linux 2 (AL2) AMIs.
 {{% /alert %}}
 
 {{% alert title="Note" color="primary" %}}
@@ -846,6 +852,54 @@ Specify using ids:
     - id: "ami-456"
 ```
 
+## spec.capacityReservationSelectorTerms
+
+Capacity Reservation Selector Terms allow you to select [on-demand capacity reservations](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-capacity-reservations.html), which will be made available to NodePools which select the given EC2NodeClass.
+Karpenter will prioritize utilizing the capacity in these reservations before falling back to on-demand and spot.
+Capacity reservations can be discovered using ids or tags.
+
+This selection logic is modeled as terms.
+A term can specify an ID or a set of tags to select against.
+When specifying tags, it will select all capacity reservations accessible from the account with matching tags.
+This can be further restricted by specifying an owner ID.
+
+#### Examples
+
+Select the reservations with the given IDs:
+
+```yaml
+spec:
+  capacityReservationSelectorTerms:
+  - id: cr-123
+  - id: cr-456
+```
+
+Select the reservations by tags:
+
+```yaml
+spec:
+  capacityReservationSelectorTerms:
+  # Select all capacity reservations which have both matching tags
+  - tags:
+      key1: foo
+      key2: bar
+  # Additionally, select all capacity reservations with the following matching tag
+  - tags:
+      key3: foobar
+```
+
+Select by tags and owner ID:
+
+```yaml
+spec:
+  # Select all capacity reservations with the matching tags which are also owned by
+  # the specified account.
+  capacityReservationSelectorTerms:
+  - tags:
+      key: foo
+    ownerID: 012345678901
+```
+
 ## spec.tags
 
 Karpenter adds tags to all resources it creates, including EC2 Instances, EBS volumes, and Launch Templates. The default set of tags are listed below.

website/content/en/preview/concepts/nodepools.md

@@ -115,7 +115,7 @@ spec:
           values: ["arm64", "amd64"]
         - key: "karpenter.sh/capacity-type"
           operator: In
-          values: ["spot", "on-demand"]
+          values: ["spot", "on-demand", "reserved"]
 
   # Disruption section which describes the ways in which Karpenter can disrupt and replace Nodes
   # Configuration in this section constrains how aggressive Karpenter can be with performing operations
@@ -251,12 +251,13 @@ Karpenter supports `linux` and `windows` operating systems.
 - values
   - `spot`
   - `on-demand`
+  - `reserved`
 
 Karpenter supports specifying capacity type, which is analogous to [EC2 purchase options](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-purchasing-options.html).
 
-Karpenter prioritizes Spot offerings if the NodePool allows Spot and on-demand instances (note that in this scenario any Spot instances priced higher than the cheapest on-demand instance will be temporarily removed from consideration).
-If the provider API (e.g. EC2 Fleet's API) indicates Spot capacity is unavailable, Karpenter caches that result across all attempts to provision EC2 capacity for that instance type and zone for the next 3 minutes.
-If there are no other possible offerings available for Spot, Karpenter will attempt to provision on-demand instances, generally within milliseconds.
+If a NodePool is compatible with multiple capacity types, Karpenter will prioritize `reserved` capacity, followed by `spot`, then finally `on-demand`.
+If the provider API (e.g. EC2 Fleet's API) indicates capacity is unavailable, Karpenter caches that result across all attempts to provision EC2 capacity for that instance type and zone for the next 3 minutes.
+If there are no other possible offerings available for a higher priority capacity type, Karpenter will attempt to fallback to a lower priority capacity type, generally within milliseconds.
 
 Karpenter also allows `karpenter.sh/capacity-type` to be used as a topology key for enforcing topology-spread.
 

website/content/en/preview/concepts/scheduling.md

@@ -154,7 +154,7 @@ Take care to ensure the label domains are correct. A well known label like `karp
 | node.kubernetes.io/windows-build                               | 10.0.17763  | Windows OS build in the format "MajorVersion.MinorVersion.BuildNumber". Can be `10.0.17763` for WS2019, or `10.0.20348` for WS2022. ([k8s](https://kubernetes.io/docs/reference/labels-annotations-taints/#nodekubernetesiowindows-build)) |
 | kubernetes.io/os                                               | linux       | Operating systems are defined by [GOOS values](https://github.com/golang/go/blob/master/src/internal/syslist/syslist.go) (`KnownOS`) on the instance                            |
 | kubernetes.io/arch                                             | amd64       | Architectures are defined by [GOARCH values](https://github.com/golang/go/blob/master/src/internal/syslist/syslist.go) (`KnownArch`) on the instance                              |
-| karpenter.sh/capacity-type                                     | spot        | Capacity types include `spot`, `on-demand`                                                                                                                      |
+| karpenter.sh/capacity-type                                     | spot        | Capacity types include `reserved`, `spot`, and `on-demand`                                                                                                                      |
 | karpenter.k8s.aws/instance-hypervisor                          | nitro       | [AWS Specific] Instance types that use a specific hypervisor                                                                                                    |
 | karpenter.k8s.aws/instance-encryption-in-transit-supported     | true        | [AWS Specific] Instance types that support (or not) in-transit encryption                                                                                       |
 | karpenter.k8s.aws/instance-category                            | g           | [AWS Specific] Instance types of the same category, usually the string before the generation number                                                             |