How to add preBootstrapCommands in Karpenter NodePool/NodeClass definitions

[doverk96]

We use eksctl to provision our EKS cluster and node groups. It provides support for preBootstrapCommands which actually runs even before bootstrap script (/etc/eks/bootstrap.sh) runs.

Is there any way to achieve the same functionality in Karpenter ?
I do not want to use custom AMIs.

[edmondceausu]

If you are using the AMI families, you can specify spec.userData in your NodeClass which will prepend the userData that you specify with the default userData for that AMI family. Karpenter docs has some pretty good examples on this for the different AMI families: https://karpenter.sh/docs/concepts/nodeclasses/#specuserdata