High privileged PriorityClass causes some errors on import

[196Ikuchil]

There are 2 problems with import function of ExportService.

1. The default existing PriorityClass conflicts.

When the scheduler is restarted, 2 PriorityClassthat issystem-cluster-critical and system-node-critical will be created automatically.
The import function of ExportService calls that restart logic, at first. This means that the 2 PriorityClass are recreated before import logic.

And exported resources file(export.yml) from the export function also includes the 2 PriorityClass.
Therefore, the names of these PriorityClass are in conflict when importing the resources file(export.yml).

E0209 22:41:50.712897   74340 export.go:57] failed to import all resources: import resources all:
    github.com/kubernetes-sigs/kube-scheduler-simulator/export.(*Service).Import
        /Users/username/kube-scheduler-simulator/export/export.go:225
  - apply resources:
    github.com/kubernetes-sigs/kube-scheduler-simulator/export.(*Service).apply
        /Users/username/kube-scheduler-simulator/export/export.go:196
  - apply PriorityClass:
    github.com/kubernetes-sigs/kube-scheduler-simulator/export.(*Service).applyPcs.func1
        /Users/username/kube-scheduler-simulator/export/export.go:369
  - apply priorityClass:
    github.com/kubernetes-sigs/kube-scheduler-simulator/priorityclass.(*Service).Apply
        /Users/username/kube-scheduler-simulator/priorityclass/priorityclass.go:47
  - Operation cannot be fulfilled on priorityclasses.scheduling.k8s.io "system-cluster-critical": the object has been modified; please apply your changes to the latest version and try again
{"time":"2022-02-09T22:41:50.713011+09:00","id":"","remote_ip":"127.0.0.1","host":"localhost:1212","method":"POST","uri":"/api/v1/import","user_agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:96.0) Gecko/20100101 Firefox/96.0","status":500,"error":"code=500, message=Internal Server Error","latency":147452615,"latency_human":"147.452615ms","bytes_in":6097,"bytes_out":36}

2. Permission to create the priorityclass

The import function tries to create a priority class that names with 'system-' prefix when an imported resources file includes PriorityClass like a system-cluster-critical or system-node-critical.
But that gets this permission's error.

E0209 22:58:57.957848   74651 priorityclass.go:36] failed to apply priorityClass: apply priorityClass:
    github.com/kubernetes-sigs/kube-scheduler-simulator/priorityclass.(*Service).Apply
        /Users/username/kube-scheduler-simulator/priorityclass/priorityclass.go:47
  - PriorityClass.scheduling.k8s.io "system-priority-class1" is invalid: metadata.name: Forbidden: priority class names with 'system-' prefix are reserved for system use only. error: system-priority-class1 is not a known system priority class

Would you give me some good ideas, please?

/kind bug
/assign

[sanposhiho]

I suggest not to export system-cluster-critical and system-node-critical. They are created automatically, so exporting them doesn't make much sense.