Bottle-Rocket in EKS for pre fetched image not working

I understand you're experiencing issues with prefetching ECR images in Bottlerocket instances for use with Amazon EKS. This is a complex process that involves several steps, and there could be multiple reasons why it's not working as expected.

First, let's review the process you're trying to implement:

1. Fetch ECR images into Bottlerocket instances
2. Create snapshots of these instances
3. Use the snapshot ID in Karpenter nodepool configuration
4. Create custom nodes for large images

The fact that the image is running when using the standard Bottlerocket AMI, but not with prefetching, suggests that the issue likely lies in the prefetching process or how the snapshot is being utilized.

Here are some potential areas to investigate:

1. Ensure that the script for prefetching images is correctly pulling the desired images into the Bottlerocket data volume. Bottlerocket provides a specific volume for container data, which should be used for this purpose.

2. Verify that the EBS snapshot creation process is capturing the prefetched images correctly. The snapshot should include the Bottlerocket data volume with the prefetched images.

3. Check your Karpenter nodepool configuration to ensure it's correctly referencing the snapshot ID and other necessary parameters.

4. Examine the Bottlerocket bootstrap process when launching new nodes. Ensure that the bootstrap script is correctly mounting and utilizing the data volume with prefetched images.

5. Review the logs of the container runtime (likely containerd) on the Bottlerocket instances to see if there are any errors related to image pulling or usage.

6. Verify that the IAM roles and permissions associated with your EKS nodes and Karpenter are correctly set up to allow access to the ECR images and the EBS snapshots.

7. If you're using custom Bottlerocket settings, ensure they don't interfere with the prefetched image usage.

Without more specific error messages or logs, it's challenging to pinpoint the exact issue. I recommend thoroughly reviewing each step of your process, particularly focusing on how the prefetched images are being stored and accessed during node creation and container startup.

If you continue to face issues, it would be helpful to gather more detailed logs from the Bottlerocket instances, particularly during the node joining process and container startup. This information could provide more insights into where exactly the process is failing.

Remember that Bottlerocket has a different architecture compared to traditional Linux distributions, so some standard troubleshooting methods may need to be adapted.
Sources
Reduce container startup time on Amazon EKS with Bottlerocket data volume | Containers
Difference between EKS AMI and Bottle Rocket | AWS re:Post
Create nodes with optimized Bottlerocket AMIs - Amazon EKS