[Umbrella] Enhancement of WorkloadRebalancer to support fresh rescheduling across multiple cluster affinities

[chaosi-zju]

What would you like to be added:

Enhancement of WorkloadRebalancer to support fresh rescheduling across multiple cluster affinities.

Why is this needed:

In summary, what has been discussed in this thread is what the concerns are ie. lack of ability to do a fresh reschedule where the workloads need to be relocated back to the original clusters where the conditions are satisfied (either due to re-availability of capacity or the cluster becoming available if there was a failover etc). Currently no construct of Karmada enables this reverse migration workflow. Almost all the scheduling flows taking into account the previous scheduling context.

I see WorkloadRebalancer as a natural fit to solve this by providing a control to the user to signal a fresh reschedule (preferably through a field spec.freshReschedule) without honoring the previous schedule context. Such reschedules may or may not cause the workload to be relocated depending on where it was scheduled prior. It is upto the user who triggers it to decide when a fresh reschedule is triggered via WorkloadRebalancer and that the user is fully aware of the implications of such an action. Users may build workflows to trigger any periodic fresh reschedules as well to suit their needs.

related issue: #5070、#4990

TODO list

• share opinion in Community Meeting
• proposal
• implementation
• UT test
• e2e test

[chaosi-zju]

/assign @bharathguvvala

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/assign @bharathguvvala

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[bharathguvvala]

Commenting so that the issue can be assigned to me.

/assign @bharathguvvala