fix: Karpenter 1.0 installation fails to create default EC2NodeClass

[JoeNorth]

Issue #249

Description of changes:

• Fixed misspelled function names for getting EKS AMIs.

• Updated the logic for getting EKS AMIs for the default EC2NodeClass.

With the release of Karpenter v1.0 spec.amiSelectorTerms is now a required field for EC2NodeClass. This posed an issue as the previous logic did not create this field for Bottlerocket AMIs and thus caused the default EC2NodeClass creation to fail.

Starting with Karpenter v1.0, spec.amiSelectorTerms.alias is now available. The proposed changes simplify this logic so that only the amiFamily and latest AMI release version need to be known and Karpenter will figure out the AMIs to be used.

The alias field is now passed to the default EC2NodeClass in the format ami-family@ami-version. For example:

amiSelectorTerms:
  - alias: al2@v20240904

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[aaroniscode]

Hi @JoeNorth

I'm aiming for the install karpenter to match the Getting Started Guide as close as possible and in Step 5. Create NodePool the example uses amiSelectorTerms with specific AMI IDs which is best practice.

Your PR removes the AMI ID's list and replaces with an alias. I'm OK with having an option flag to set an alias, though I'd like the default to match the Getting Started Guide. I think this needs to just add a lookup for Bottlerocket AMI's.

If you aren't familiar with this code I'm happy to add it to your PR, just let me know.

[JoeNorth]

Thanks for the feedback @aaroniscode. I can see where sticking with the resolved AMI IDs would be a good default.

For now I'll remove the alias support and keep this PR to just fixing the immediate issue. Support for the optional alias param can be a separate feature PR down the road.