Goal

Introduce a new feature gate in CDI and HCO that enables the same-as-target scratch space selection logic. This feature gate will be off by-default for this release.

User Stories

• As a VM owner I want to use the same storage class for all provisioning of a particular disk (including scratch space). When I provision a disk on a non-default storage class I want to use that same storage class for scratch space (not the default storage class).

Non-Requirements

• List of things not included in this epic, to alleviate any doubt raised during the grooming process.

Notes

Certain CDI operations require a scratch space PVC. This PVC is automatically allocated by CDI when needed according to the following rules:

• Use the storage class defined in the optional scratchSpaceStorageClass HCO config item
• Use the virt-default storage class
• Use the default storage class

We want to switch to the following logic which aligns more closely with customer expectations:

• Use the storage class defined in the optional scratchSpaceStorageClass HCO config item
• Use the same storage class as the target PVC

We are completing this change in semantics over three steps in order to ensure that there are no disruptions:
1. Introduce a new FG (off by-default) that enables the new behavior.
2. Turn the FG on by-default so the new behavior is default but can be disabled.
3. Remove the FG to keep only the new behavior.