`Get` method within the fake clientset returns an object that would not be normally returned when using the real clientset. Reproducer:
```go
package main
import (
v1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes/fake"
)
func main () {
cm := &v1.ConfigMap{
ObjectMeta: metav1.ObjectMeta{Namespace: metav1.NamespaceSystem, Name: "cm"},
}
client := fake.NewSimpleClientset(cm)
obj, err := client.CoreV1().ConfigMaps("").Get("", metav1.GetOptions{})
if err != nil {
panic(err)
}
fmt.Printf("obj: %#v\n", obj)
}
```
stored under `test.go` of `github.com/kubernetes/kubernetes` (master HEAD) root directory and ran:
```sh
$ go run test.go
obj: &v1.ConfigMap{TypeMeta:v1.TypeMeta{Kind:"", APIVersion:""}, ObjectMeta:v1.ObjectMeta{Name:"cm", GenerateName:"", Namespace:"kube-system", SelfLink:"", UID:"", ResourceVersion:"", Generation:0, CreationTimestamp:v1.Time{Time:time.Time{wall:0x0, ext:0, loc:(*time.Location)(nil)}}, DeletionTimestamp:(*v1.Time)(nil), DeletionGracePeriodSeconds:(*int64)(nil), Labels:map[string]string(nil), Annotations:map[string]string(nil), OwnerReferences:[]v1.OwnerReference(nil), Finalizers:[]string(nil), ClusterName:"", ManagedFields:[]v1.ManagedFieldsEntry(nil)}, Data:map[string]string(nil), BinaryData:map[string][]uint8(nil)}
```
As you can see fake clientset with a "test" configmap is created. When getting the object through the clientset back, I intentionally set the object name to an empty string. I would expect to get an error saying config map "" was not found. However, I get "test" configmap instead.
Reason for that is inside implementation of `filterByNamespaceAndName` private function:
```go
func filterByNamespaceAndName(objs []runtime.Object, ns, name string) ([]runtime.Object, error) {
var res []runtime.Object
for _, obj := range objs {
acc, err := meta.Accessor(obj)
if err != nil {
return nil, err
}
if ns != "" && acc.GetNamespace() != ns {
continue
}
if name != "" && acc.GetName() != name {
continue
}
res = append(res, obj)
}
return res, nil
}
```
When `name` is empty, `name != "" && acc.GetName() != name` condition is false and thus `obj` is consider as a fit.
[1] https://github.com/kubernetes/client-go/blob/master/testing/fixture.go#L481-L493
This patch moves the HostUtil functionality from the util/mount package
to the volume/util/hostutil package.
All `*NewHostUtil*` calls are changed to return concrete types instead
of interfaces.
All callers are changed to use the `*NewHostUtil*` methods instead of
directly instantiating the concrete types.
DesiredStateOfWorldPopulator should skip a volume that is not used in any
pod. "Used" means either mounted (via volumeMounts) or used as raw block
device (via volumeDevices).
Especially when block feature is disabled, a block volume must not get into
DesiredStateOfWorld, because it would be formatted and mounted there.
This patch refactors pkg/util/mount to be more usable outside of
Kubernetes. This is done by refactoring mount.Interface to only contain
methods that are not K8s specific. Methods that are not relevant to
basic mount activities but still have OS-specific implementations are
now found in a mount.HostUtils interface.
