Resource handler returned message: "Invalid request provided: Invalid AppType [KernelGateway]. This AppType has been deprecated.

It looks like you're encountering an error when trying to follow the machine learning tutorial for training a model on AWS. The error message indicates that the "KernelGateway" AppType has been deprecated, which is causing your CloudFormation stack creation to fail.

This error is likely occurring because the tutorial you're following might be using older configurations that are no longer supported in the current AWS environment. The "KernelGateway" was a type of application used in Amazon SageMaker, but it appears to have been deprecated in favor of newer approaches.

To resolve this issue, you might want to:

1. Check if there's an updated version of the tutorial that uses current AWS configurations
2. Look for alternative AWS machine learning tutorials that use Trainium (Trn1/Trn1n) instances, as these are specifically designed for ML training workloads
3. Consider exploring the AWS Neuron samples and tutorials that are available for various ML models like BERT, GPT, Llama, and others

AWS provides numerous up-to-date samples and tutorials for training various machine learning models using their Trainium instances, including encoder models (BERT, RoBERTa), decoder models (GPT, Llama), vision transformers, and more. These resources would likely provide you with a more current approach to ML model training on AWS.
Sources
https://awsdocs-neuron.readthedocs-hosted.com/en/latest/_sources/general/models/training-trn1-samples.rst
https://awsdocs-neuron.readthedocs-hosted.com/en/latest/_sources/general/models/training-trn1-samples.rst.txt