Avoid looking up instance id until we need it

currently kube-controller-manager cannot run outside of a vm started by openstack (with --cloud-provider=openstack params). We try to read the instance id from the metadata provider or the config drive or the file location only when we really need it. In the normal scenario, the controller-manager uses the node name to get the instance id. https://github.com/kubernetes/kubernetes/blob/41541910e1699975a8f9202a89b6865e45921194/pkg/volume/cinder/attacher.go#L149 The localInstanceID is currently used only in the test case, so let us not read it until it is really needed.

Avoid looking up instance id until we need it
6139f9ab · Davanum Srinivas · 2853f46b · 6139f9ab · 6139f9ab · 6139f9ab
Commit 6139f9ab authored Jul 20, 2017 by Davanum Srinivas
3 changed files
--- a/pkg/cloudprovider/providers/openstack/openstack.go
+++ b/pkg/cloudprovider/providers/openstack/openstack.go
@@ -280,18 +280,12 @@ func newOpenStack(cfg Config) (*OpenStack, error) {
 		return nil, err
 	}
-	id, err := readInstanceID()
-	if err != nil {
-		return nil, err
-	}
 	os := OpenStack{
-		provider:        provider,
+		provider:  provider,
-		region:          cfg.Global.Region,
+		region:    cfg.Global.Region,
-		lbOpts:          cfg.LoadBalancer,
+		lbOpts:    cfg.LoadBalancer,
-		bsOpts:          cfg.BlockStorage,
+		bsOpts:    cfg.BlockStorage,
-		routeOpts:       cfg.Route,
+		routeOpts: cfg.Route,
-		localInstanceID: id,
 	}
 	err = checkOpenStackOpts(&os)

--- a/pkg/cloudprovider/providers/openstack/openstack_instances.go
+++ b/pkg/cloudprovider/providers/openstack/openstack_instances.go
@@ -143,6 +143,13 @@ func (i *Instances) ExternalID(name types.NodeName) (string, error) {
 // InstanceID returns the kubelet's cloud provider ID.
 func (os *OpenStack) InstanceID() (string, error) {
+	if len(os.localInstanceID) == 0 {
+		id, err := readInstanceID()
+		if err != nil {
+			return "", err
+		}
+		os.localInstanceID = id
+	}
 	return os.localInstanceID, nil
 }

--- a/pkg/cloudprovider/providers/openstack/openstack_test.go
+++ b/pkg/cloudprovider/providers/openstack/openstack_test.go
@@ -473,7 +473,12 @@ func TestVolumes(t *testing.T) {
 	WaitForVolumeStatus(t, os, vol, volumeAvailableStatus)
-	diskId, err := os.AttachDisk(os.localInstanceID, vol)
+	id, err := os.InstanceID()
+	if err != nil {
+		t.Fatalf("Cannot find instance id: %v", err)
+	}
+	diskId, err := os.AttachDisk(id, vol)
 	if err != nil {
 		t.Fatalf("Cannot AttachDisk Cinder volume %s: %v", vol, err)
 	}
@@ -487,7 +492,7 @@ func TestVolumes(t *testing.T) {
 	}
 	t.Logf("Volume (%s) found at path: %s\n", vol, devicePath)
-	err = os.DetachDisk(os.localInstanceID, vol)
+	err = os.DetachDisk(id, vol)
 	if err != nil {
 		t.Fatalf("Cannot DetachDisk Cinder volume %s: %v", vol, err)
 	}