WIP: Proposal for dedicated hosts #5230
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,100 @@ | ||
| --- | ||
| title: Add Support for EC2 Dedicated Hosts | ||
| authors: | ||
| - "@faermanj" | ||
| reviewers: | ||
| creation-date: 2024-11-25 | ||
| last-updated: 2024-11-25 | ||
| status: draft | ||
| see-also: [] | ||
| replaces: [] | ||
| superseded-by: [] | ||
| --- | ||
|
|
||
| # Add Support for EC2 Dedicated Hosts | ||
|
|
||
| ## Table of Contents | ||
|
|
||
| - [Add Support for EC2 Dedicated Hosts](#start) | ||
| - [Table of Contents](#table-of-contents) | ||
| - [Glossary](#glossary) | ||
| - [Summary](#summary) | ||
| - [Motivation](#motivation) | ||
| - [Goals](#goals) | ||
| - [Non-Goals/Future Work](#non-goalsfuture-work) | ||
| - [Proposal](#proposal) | ||
| - [User Stories](#user-stories) | ||
| - [Story 1](#story-1) | ||
| - [Requirements](#requirements) | ||
| - [Functional Requirements](#functional-requirements) | ||
| - [Non-Functional Requirements](#non-functional-requirements) | ||
| - [Implementation Details/Notes/Constraints](#implementation-detailsnotesconstraints) | ||
| - [Security Model](#security-model) | ||
| - [Risks and Mitigations](#risks-and-mitigations) | ||
| - [Alternatives](#alternatives) | ||
| - [Upgrade Strategy](#upgrade-strategy) | ||
| - [Additional Details](#additional-details) | ||
| - [Test Plan](#test-plan) | ||
| - [Graduation Criteria](#graduation-criteria) | ||
| - [Implementation History](#implementation-history) | ||
|
|
||
| ## Glossary | ||
|
|
||
| - [CAPA](https://cluster-api.sigs.k8s.io/reference/glossary.html#capa) - Cluster API Provider AWS. | ||
| - [CAPI](https://github.com/kubernetes-sigs/cluster-api) - Cluster API | ||
|
|
||
| ## Summary | ||
| The "Dedicated Hosts" feature of Amazon EC2 lets customers allocate physical hosts, with explicit hardware capacity, and allocate instances on those hosts. Also, instances on dedicated hosts have an "affinity" setting (Default or Host affinity), specifying the instance behavior on stopping and restarting the instance. | ||
| More information can be found on the [dedicated hosts feature documentation](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/dedicated-hosts-overview.html). | ||
| This proposal is for adding support of that feature on CAPA, allowing users to leverage the provider feature. | ||
|
|
||
| ## Motivation | ||
| Dedicated hosts are primarily used for licensing compliance, when the required software (i.e. enterprise databases) needs to account for the physical host capacity for licensing. Also, it is a mechanism that can control explicitly which instances are executed on the same hosts, that might be relevant in scenarios related to security and performance predictability. | ||
|
|
||
| ### Goals | ||
| 1. On cluster creation, let users specify the host id and affinity for instances. | ||
|
|
||
| ### Non-Goals/Future Work | ||
| - Dedicated Host allocation. For now, dedicated hosts must be pre-allocated and explicitly configured. In future work, we may want to auto-allocate / release dedicated hosts. | ||
| - Custom replica allocation policy. For now, replicas are allocated in the first dedicated host that accepts the instance. In future work, we may let users configure other policies (round-robin, least-utilized, ...) | ||
|
|
||
| ## Proposal | ||
| - Add list host id and affinity to the proper kind spec (`AWSMachineTemplate`?). | ||
| - Define and document the initial policy for instance allocation | ||
| - Add an E2E test case | ||
|
|
||
|
|
||
| ### Risks and Mitigations | ||
|
There was a problem hiding this comment. Is there any risk of control planes "losing" HW HA when allocating control planes in the same host, or will the proposal covers only the EC2 instances for worker/compute nodes? There was a problem hiding this comment. Would it be reasonable to require a minimum of 3 dedicated hosts? |
||
|
|
||
|
|
||
| ## Alternatives | ||
|
|
||
| Manually configuring the cluster, setting the appropriate host affinities to match the desired dedicated hosts. | ||
|
|
||
| #### Benefits | ||
|
|
||
| - Let enterprise customers stay compliant with licensing policies and other dedicated hosts applications. | ||
|
|
||
| #### Downsides | ||
|
|
||
| - "Instance to host" mapping might be too much for CAPA to manage. | ||
|
|
||
| #### Decision | ||
|
|
||
| ## Upgrade Strategy | ||
| No impact on upgrades. | ||
|
|
||
| ## Additional Details | ||
|
|
||
| ### Test Plan | ||
| * Test creating a cluster, confirm all instances are executed on their respective dedicated hosts. | ||
|
|
||
| ### Graduation Criteria | ||
|
|
||
| ## Implementation History | ||
|
|
||
| - [x] 2024-11-25: Open proposal (PR) | ||
|
|
||
| <!-- Links --> | ||
| [ec2 dedicated hosts]: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/dedicated-hosts-overview.html | ||
| [discussion]: https://github.com/kubernetes-sigs/cluster-api-provider-aws/discussions/5213 | ||
Oops, something went wrong.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Where is this available in the instance object exposed by the AWS client?