Added openstack instance metadata search order

Author: richardalberto

pkg/cloudprovider/providers/openstack/metadata.go

@@ -32,17 +32,25 @@ import (
 	"k8s.io/utils/exec"
 )
 
-// metadataUrl is URL to OpenStack metadata server. It's hardcoded IPv4
-// link-local address as documented in "OpenStack Cloud Administrator Guide",
-// chapter Compute - Networking with nova-network.
-// https://docs.openstack.org/admin-guide/compute-networking-nova.html#metadata-service
-const metadataUrl = "http://169.254.169.254/openstack/2012-08-10/meta_data.json"
-
-// Config drive is defined as an iso9660 or vfat (deprecated) drive
-// with the "config-2" label.
-// http://docs.openstack.org/user-guide/cli-config-drive.html
-const configDriveLabel = "config-2"
-const configDrivePath = "openstack/2012-08-10/meta_data.json"
+const (
+	// metadataUrl is URL to OpenStack metadata server. It's hardcoded IPv4
+	// link-local address as documented in "OpenStack Cloud Administrator Guide",
+	// chapter Compute - Networking with nova-network.
+	// https://docs.openstack.org/admin-guide/compute-networking-nova.html#metadata-service
+	metadataUrl = "http://169.254.169.254/openstack/2012-08-10/meta_data.json"
+
+	// metadataID is used as an identifier on the metadata search order configuration.
+	metadataID = "metadataService"
+
+	// Config drive is defined as an iso9660 or vfat (deprecated) drive
+	// with the "config-2" label.
+	// http://docs.openstack.org/user-guide/cli-config-drive.html
+	configDriveLabel = "config-2"
+	configDrivePath  = "openstack/2012-08-10/meta_data.json"
+
+	// configDriveID is used as an identifier on the metadata search order configuration.
+	configDriveID = "configDrive"
+)
 
 var ErrBadMetadata = errors.New("Invalid OpenStack metadata, got empty uuid")
 
@@ -141,12 +149,27 @@ func getMetadataFromMetadataService() (*Metadata, error) {
 // Metadata is fixed for the current host, so cache the value process-wide
 var metadataCache *Metadata
 
-func getMetadata() (*Metadata, error) {
+func getMetadata(order string) (*Metadata, error) {
 	if metadataCache == nil {
-		md, err := getMetadataFromConfigDrive()
-		if err != nil {
-			md, err = getMetadataFromMetadataService()
+		var md *Metadata
+		var err error
+
+		elements := strings.Split(order, ",")
+		for _, id := range elements {
+			switch id {
+			case configDriveID:
+				md, err = getMetadataFromConfigDrive()
+			case metadataID:
+				md, err = getMetadataFromMetadataService()
+			default:
+				err = fmt.Errorf("%s is not a valid metadata search order option. Supported options are %s and %s", id, configDriveID, metadataID)
+			}
+
+			if err == nil {
+				break
+			}
 		}
+
 		if err != nil {
 			return nil, err
 		}

pkg/cloudprovider/providers/openstack/openstack.go

@@ -100,13 +100,18 @@ type RouterOpts struct {
 	RouterId string `gcfg:"router-id"` // required
 }
 
+type MetadataOpts struct {
+	SearchOrder string `gcfg:"search-order"`
+}
+
 // OpenStack is an implementation of cloud provider Interface for OpenStack.
 type OpenStack struct {
-	provider  *gophercloud.ProviderClient
-	region    string
-	lbOpts    LoadBalancerOpts
-	bsOpts    BlockStorageOpts
-	routeOpts RouterOpts
+	provider     *gophercloud.ProviderClient
+	region       string
+	lbOpts       LoadBalancerOpts
+	bsOpts       BlockStorageOpts
+	routeOpts    RouterOpts
+	metadataOpts MetadataOpts
 	// InstanceID of the server where this OpenStack object is instantiated.
 	localInstanceID string
 }
@@ -128,6 +133,7 @@ type Config struct {
 	LoadBalancer LoadBalancerOpts
 	BlockStorage BlockStorageOpts
 	Route        RouterOpts
+	Metadata     MetadataOpts
 }
 
 func init() {
@@ -181,6 +187,7 @@ func readConfig(config io.Reader) (Config, error) {
 	// Set default values for config params
 	cfg.BlockStorage.BSVersion = "auto"
 	cfg.BlockStorage.TrustDevicePath = false
+	cfg.Metadata.SearchOrder = fmt.Sprintf("%s,%s", configDriveID, metadataID)
 
 	err := gcfg.ReadInto(&cfg, config)
 	return cfg, err
@@ -198,7 +205,7 @@ func (c *Caller) Call(f func()) {
 	}
 }
 
-func readInstanceID() (string, error) {
+func readInstanceID(searchOrder string) (string, error) {
 	// Try to find instance ID on the local filesystem (created by cloud-init)
 	const instanceIDFile = "/var/lib/cloud/data/instance-id"
 	idBytes, err := ioutil.ReadFile(instanceIDFile)
@@ -212,7 +219,7 @@ func readInstanceID() (string, error) {
 		// Fall through to metadata server lookup
 	}
 
-	md, err := getMetadata()
+	md, err := getMetadata(searchOrder)
 	if err != nil {
 		return "", err
 	}
@@ -275,16 +282,19 @@ func newOpenStack(cfg Config) (*OpenStack, error) {
 		err = openstack.Authenticate(provider, cfg.toAuthOptions())
 	}
 
+	err = validateMetadataSearchOrder(cfg.Metadata.SearchOrder)
+
 	if err != nil {
 		return nil, err
 	}
 
 	os := OpenStack{
-		provider:  provider,
-		region:    cfg.Global.Region,
-		lbOpts:    cfg.LoadBalancer,
-		bsOpts:    cfg.BlockStorage,
-		routeOpts: cfg.Route,
+		provider:     provider,
+		region:       cfg.Global.Region,
+		lbOpts:       cfg.LoadBalancer,
+		bsOpts:       cfg.BlockStorage,
+		routeOpts:    cfg.Route,
+		metadataOpts: cfg.Metadata,
 	}
 
 	err = checkOpenStackOpts(&os)
@@ -539,7 +549,7 @@ func (os *OpenStack) Zones() (cloudprovider.Zones, bool) {
 }
 
 func (os *OpenStack) GetZone() (cloudprovider.Zone, error) {
-	md, err := getMetadata()
+	md, err := getMetadata(os.metadataOpts.SearchOrder)
 	if err != nil {
 		return cloudprovider.Zone{}, err
 	}
@@ -742,3 +752,27 @@ func (os *OpenStack) volumeService(forceVersion string) (volumeService, error) {
 		return nil, errors.New(err_txt)
 	}
 }
+
+func validateMetadataSearchOrder(order string) error {
+	if order == "" {
+		return errors.New("Invalid value in section [Metadata] with key `search-order`. Value cannot be empty")
+	}
+
+	elements := strings.Split(order, ",")
+	if len(elements) > 2 {
+		return errors.New("Invalid value in section [Metadata] with key `search-order`. Value cannot contain more than 2 elements")
+	}
+
+	for _, o := range elements {
+		switch o {
+		case configDriveID:
+		case metadataID:
+		default:
+			errTxt := "Invalid element '%s' found in section [Metadata] with key `search-order`." +
+				"Supported elements include '%s' and '%s'"
+			return fmt.Errorf(errTxt, o, configDriveID, metadataID)
+		}
+	}
+
+	return nil
+}

pkg/cloudprovider/providers/openstack/openstack_instances.go

@@ -32,6 +32,7 @@ import (
 
 type Instances struct {
 	compute *gophercloud.ServiceClient
+	opts    MetadataOpts
 }
 
 // Instances returns an implementation of Instances for OpenStack.
@@ -45,13 +46,16 @@ func (os *OpenStack) Instances() (cloudprovider.Instances, bool) {
 
 	glog.V(1).Info("Claiming to support Instances")
 
-	return &Instances{compute}, true
+	return &Instances{
+		compute: compute,
+		opts:    os.metadataOpts,
+	}, true
 }
 
 // Implementation of Instances.CurrentNodeName
 // Note this is *not* necessarily the same as hostname.
 func (i *Instances) CurrentNodeName(hostname string) (types.NodeName, error) {
-	md, err := getMetadata()
+	md, err := getMetadata(i.opts.SearchOrder)
 	if err != nil {
 		return "", err
 	}
@@ -119,7 +123,7 @@ func (i *Instances) InstanceExistsByProviderID(providerID string) (bool, error)
 // InstanceID returns the kubelet's cloud provider ID.
 func (os *OpenStack) InstanceID() (string, error) {
 	if len(os.localInstanceID) == 0 {
-		id, err := readInstanceID()
+		id, err := readInstanceID(os.metadataOpts.SearchOrder)
 		if err != nil {
 			return "", err
 		}