We'd better not depend on a kubeconfig file

[lowang-bh]

https://github.com/VasuDevrani/volcano/actions/runs/9105698087/job/25031701446?pr=1

E0516 02:53:19.986663   39759 utils.go:43] init kubeclient in 4pdvgpu failed: stat /home/runner/.kube/config: no such file or directory
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x16d78bd]

goroutine 1 [running]:
volcano.sh/apis/pkg/client/clientset/versioned.NewForConfig(0x0?)
	/home/runner/go/pkg/mod/volcano.sh/apis@v1.9.0/pkg/client/clientset/versioned/clientset.go:92 +0x1d
volcano.sh/apis/pkg/client/clientset/versioned.NewForConfigOrDie(...)
	/home/runner/go/pkg/mod/volcano.sh/apis@v1.9.0/pkg/client/clientset/versioned/clientset.go:153
volcano.sh/volcano/test/e2e/jobp.TestMain(0x1c51e00?)
	/home/runner/work/volcano/volcano/test/e2e/jobp/main_test.go:35 +0x67
main.main()
	_testmain.go:83 +0x1e6
FAIL	volcano.sh/volcano/test/e2e/jobp	0.023s
E0516 02:53:19.986155   39760 utils.go:43] init kubeclient in 4pdvgpu failed: stat /home/runner/.kube/config: no such file or directory
panic: runtime error: invalid memory address or nil pointer dereference

code at

volcano/pkg/scheduler/api/devices/nvidia/vgpu/utils.go

Lines 39 to 65 in 63bf271

	func init() {
	var err error
	kubeClient, err = NewClient()
	if err != nil {
	klog.Errorf("init kubeclient in hamivgpu failed: %s", err.Error())
	} else {
	klog.V(3).Infoln("init kubeclient success")
	}
	}
	// NewClient connects to an API server
	func NewClient() (kubernetes.Interface, error) {
	kubeConfig := os.Getenv("KUBECONFIG")
	if kubeConfig == "" {
	kubeConfig = filepath.Join(os.Getenv("HOME"), ".kube", "config")
	}
	config, err := rest.InClusterConfig()
	if err != nil {
	config, err = clientcmd.BuildConfigFromFlags("", kubeConfig)
	if err != nil {
	return nil, err
	}
	}
	client, err := kubernetes.NewForConfig(config)
	kubeClient = client
	return client, err
	}

What would you like to be added:

The scheduler has its own service account. We'd better not to depend on a config file.

Why is this needed:

more compatible and portability

[lowang-bh]

@Monokaix @archlitchi

[Monokaix]

When will this ut failed?