Description

Is there an existing issue for this?

• I have searched the existing issues

Is an existing page relevant?

https://karpenter.sh/docs/concepts/nodeclasses/#raid0

What karpenter features are relevant?

instanceStorePolicy, Bottlerocket AMI

How should the docs be improved?

The current instanceStorePolicy documentation explains how to configure ephemeral storage for "d" instance types with RAID0, but it's incomplete and misleading for Bottlerocket users.

Current state:
The documentation states:

• AL2: "Karpenter automatically configures the disks"
• AL2023: "Karpenter automatically configures the disks"
• Others: "For all other AMI families, you must configure the disks yourself"

The problem:
Since Karpenter v1.1.0 (PR #7044), Bottlerocket also has automatic disk configuration, but this is not documented. This causes confusion:

1. New users following the docs think they need to manually configure ephemeral storage for Bottlerocket
2. Users upgrading from v1.0.x to v1.1.0+ experience bootstrap failures when their manual userData configuration conflicts with Karpenter's automatic configuration
3. The documentation explicitly says "For all other AMI families, you must configure the disks yourself", which is incorrect for Bottlerocket

Proposed fix:
Add a Bottlerocket section to the RAID0 documentation that explicitly states:

Bottlerocket

On Bottlerocket, Karpenter automatically configures the disks via bootstrap commands (apiclient ephemeral-storage init and apiclient ephemeral-storage bind). You should not add these commands to your userData, as they will conflict with Karpenter's automatic configuration and cause bootstrap failures.

Additional context:

• Related issue from kubernetes-sigs/karpenter: Using karpenter with bottlerocket kubernetes-sigs/karpenter#2282
• PR that added auto-configuration: feat: Allow instance store policy to be configured on BR family #7044
• This change was documented in the upgrade guide for v1.1.0, but new users deploying latest versions would not check upgrade guides

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