Merge pull request kubernetes#51087 from oracle/for/upstream/master/c…

…cm-instance-exists

Automatic merge from submit-queue (batch tested with PRs 51174, 51363, 51087, 51382, 51388)

Add InstanceExistsByProviderID to cloud provider interface for CCM

**What this PR does / why we need it**:

Currently, [`MonitorNode()`](https://github.com/kubernetes/kubernetes/blob/02b520f0a40be2056d91fc0661c2b4fdb2694c30/pkg/controller/cloud/nodecontroller.go#L240) in the node controller checks with the CCM if a node still exists by calling `ExternalID(nodeName)`. `ExternalID` is supposed to return the provider id of a node which is not supported on every cloud. This means that any clouds who cannot infer the provider id by the node name from a remote location will never remove nodes that no longer exist. 


**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes kubernetes#50985

**Special notes for your reviewer**:

We'll want to create a subsequent issue to track the implementation of these two new methods in the cloud providers.

**Release note**:

```release-note
Adds `InstanceExists` and `InstanceExistsByProviderID` to cloud provider interface for the cloud controller manager
```

/cc @wlan0 @thockin @andrewsykim @luxas @jhorwit2

/area cloudprovider
/sig cluster-lifecycle

pkg/cloudprovider/providers/openstack/openstack_instances.go

@@ -110,6 +110,12 @@ func (i *Instances) ExternalID(name types.NodeName) (string, error) {
 	return srv.ID, nil
 }
 
+// InstanceExistsByProviderID returns true if the instance with the given provider id still exists and is running.
+// If false is returned with no error, the instance will be immediately deleted by the cloud controller manager.
+func (i *Instances) InstanceExistsByProviderID(providerID string) (bool, error) {
+	return false, errors.New("unimplemented")
+}
+
 // InstanceID returns the kubelet's cloud provider ID.
 func (os *OpenStack) InstanceID() (string, error) {
 	if len(os.localInstanceID) == 0 {

pkg/volume/cinder/attacher_test.go

@@ -650,6 +650,10 @@ func (instances *instances) InstanceTypeByProviderID(providerID string) (string,
 	return "", errors.New("Not implemented")
 }
 
+func (instances *instances) InstanceExistsByProviderID(providerID string) (bool, error) {
+	return false, errors.New("unimplemented")
+}
+
 func (instances *instances) List(filter string) ([]types.NodeName, error) {
 	return []types.NodeName{}, errors.New("Not implemented")
 }