Support the configuration of seeds within the same region as the shoot [KIM/feature]

[tobiscr]

Description

As part of EPIC kyma-project/kyma#18182, we are going to offer customers the option request a shoot and seed in the same region.

This requires a modification of KIM to be able to

• Receive the information that seed and shoot should be in the same region (will be an additional boolean flag in RuntimeCR)
• Set the proper fields in the Shoot-spec for Gardener (label-selectors for seeds)

AC:

• KIM contract (RuntimeCR) gets extended to support a boolean-field which indicates whether seed and shoot have to be in the same region
• If this field is set, the Shoot-spec includes the required configuration (label-selectors for seed) to enforce that the shoot will only be created if a corresponding seed exists
• Failure cases during the shoot provisioning (e.g. shoot hangs forever in Pending state) are detected and returned as failure to KEB.
• Fail fast: Before creating the Shoot-spec, KIM will evaluate whether a seed exists in the requested region. If no seed exists, the RuntimeCR will go into an Error state and indicating that no matching seed was found.
  • Communicate with Gardener team and merge the proposed PR for making the Shoot-determining logic accessible for other applications (see POC: Refactoring - moving seed determiner logic into dedicated struct gardener/gardener#9843)

Reasons

Enforce seed and shoot in same region to improve latency and address security related concerns.

Attachments

Relates to
kyma-project/kyma#18182

[tobiscr]

See https://github.com/gardener/gardener/blob/v1.84.1/example/90-shoot.yaml#L365-L368 for the Shoot-spec related section that needs to be touched