Add optional StorageClass creation for AWS EFS volumes

[vlucaj]

Proposed changes

This PR adds optional StorageClass creation for AWS EFS volumes in environments where StorageClass creation is restricted. This change allows using pre-existing StorageClasses while maintaining backwards compatibility.

• Added engine.modelManager.volumes.aws.efs.storageClass.create flag (defaults to true)
• Added engine.modelManager.volumes.aws.efs.storageClass.name for custom StorageClass names
• Made StorageClass creation conditional based on the flag
• Updated PersistentVolume and PersistentVolumeClaim templates to use configurable StorageClass name

Types of changes

What types of changes does your code introduce to the Deepgram self-hosted resources?

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update or tests (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I have read the CONTRIBUTING doc
• I have tested my changes in my local self-hosted environment
  • Please describe your testing setup and methodology here
• I have added necessary documentation (if appropriate)

[vlucaj]

Default behavior (backward compatibility) - works as before

helm template charts/deepgram-self-hosted \
  --set engine.modelManager.volumes.aws.efs.enabled=true \
  --set engine.modelManager.volumes.aws.efs.fileSystemId=fs-abc \
  --set global.deepgramSecretRef=dummy-secret \
  --set kube-prometheus-stack.includeDependency=false \
  --set prometheus-adapter.includeDependency=false \
  | grep -A20 -E 'kind: (PersistentVolume|StorageClass)' \
  | grep -E 'kind: (PersistentVolume|StorageClass)|storageClassName:|^  name:'

[vlucaj]

Custom StorageClass name with creation

• create: true, name: "custom-efs-sc"

helm template charts/deepgram-self-hosted \
  --set engine.modelManager.volumes.aws.efs.enabled=true \
  --set engine.modelManager.volumes.aws.efs.storageClass.create=true \
  --set engine.modelManager.volumes.aws.efs.storageClass.name=custom-efs-sc \
  --set engine.modelManager.volumes.aws.efs.fileSystemId=fs-abc \
  --set global.deepgramSecretRef=dummy-secret \
  --set kube-prometheus-stack.includeDependency=false \
  --set prometheus-adapter.includeDependency=false \
  | grep -A20 -E 'kind: (PersistentVolume|StorageClass)' \
  | grep -E 'kind: (PersistentVolume|StorageClass)|storageClassName:|^  name:'

[vlucaj]

External StorageClass (no creation)

• create: false, name: "existing-efs-sc"

helm template charts/deepgram-self-hosted \
  --set engine.modelManager.volumes.aws.efs.enabled=true \
  --set engine.modelManager.volumes.aws.efs.storageClass.create=false \
  --set engine.modelManager.volumes.aws.efs.storageClass.name=existing-efs-sc \
  --set engine.modelManager.volumes.aws.efs.fileSystemId=fs-abc \
  --set global.deepgramSecretRef=dummy-secret \
  --set kube-prometheus-stack.includeDependency=false \
  --set prometheus-adapter.includeDependency=false \
  | grep -A20 -E 'kind: (PersistentVolume|StorageClass)' \
  | grep -E 'kind: (PersistentVolume|StorageClass)|storageClassName:|^  name:'

[vlucaj]

External StorageClass (no creation) with no name

• create: false, no name specified
• PV/PVC use default generated name

helm template charts/deepgram-self-hosted \
  --set engine.modelManager.volumes.aws.efs.enabled=true \
  --set engine.modelManager.volumes.aws.efs.storageClass.create=false \
  --set engine.modelManager.volumes.aws.efs.storageClass.name= \
  --set engine.modelManager.volumes.aws.efs.fileSystemId=fs-abc \
  --set global.deepgramSecretRef=dummy-secret \
  --set kube-prometheus-stack.includeDependency=false \
  --set prometheus-adapter.includeDependency=false \
  | grep -A20 -E 'kind: (PersistentVolume|StorageClass)' \
  | grep -E 'kind: (PersistentVolume|StorageClass)|storageClassName:|^  name:'

[vlucaj]

feature ref: #116