Reduce API calls for Azure instance metadata

pkg/cloudprovider/providers/azure/azure_instance_metadata.go

@@ -59,6 +59,13 @@ type InstanceMetadata struct {
 	baseURL string
 }
 
+// ComputeMetadata represents compute information
+type ComputeMetadata struct {
+	Name   string `json:"name,omitempty"`
+	Zone   string `json:"zone,omitempty"`
+	VMSize string `json:"vmSize,omitempty"`
+}
+
 // NewInstanceMetadata creates an instance of the InstanceMetadata accessor object.
 func NewInstanceMetadata() *InstanceMetadata {
 	return &InstanceMetadata{

pkg/cloudprovider/providers/azure/azure_instances.go

@@ -51,7 +51,12 @@ func (az *Cloud) NodeAddresses(ctx context.Context, name types.NodeName) ([]v1.N
 	}
 
 	if az.UseInstanceMetadata {
-		isLocalInstance, err := az.isCurrentInstance(name)
+		computeMetadata, err := az.getComputeMetadata()
+		if err != nil {
+			return nil, err
+		}
+
+		isLocalInstance, err := az.isCurrentInstance(name, computeMetadata.Name)
 		if err != nil {
 			return nil, err
 		}
@@ -119,23 +124,30 @@ func (az *Cloud) InstanceShutdownByProviderID(ctx context.Context, providerID st
 	return false, cloudprovider.NotImplemented
 }
 
-func (az *Cloud) isCurrentInstance(name types.NodeName) (bool, error) {
+// getComputeMetadata gets compute information from instance metadata.
-	nodeName := mapNodeNameToVMName(name)
+func (az *Cloud) getComputeMetadata() (*ComputeMetadata, error) {
-	metadataName, err := az.metadata.Text("instance/compute/name")
+	computeInfo := ComputeMetadata{}
+	err := az.metadata.Object(computeMetadataURI, &computeInfo)
 	if err != nil {
-		return false, err
+		return nil, err
 	}
 
+	return &computeInfo, nil
+}
+
+func (az *Cloud) isCurrentInstance(name types.NodeName, metadataVMName string) (bool, error) {
+	var err error
+	nodeName := mapNodeNameToVMName(name)
 	if az.VMType == vmTypeVMSS {
 		// VMSS vmName is not same with hostname, use hostname instead.
-		metadataName, err = os.Hostname()
+		metadataVMName, err = os.Hostname()
 		if err != nil {
 			return false, err
 		}
 	}
 
-	metadataName = strings.ToLower(metadataName)
+	metadataVMName = strings.ToLower(metadataVMName)
-	return (metadataName == nodeName), err
+	return (metadataVMName == nodeName), err
 }
 
 // InstanceID returns the cloud provider ID of the specified instance.
@@ -144,7 +156,12 @@ func (az *Cloud) InstanceID(ctx context.Context, name types.NodeName) (string, e
 	nodeName := mapNodeNameToVMName(name)
 
 	if az.UseInstanceMetadata {
-		isLocalInstance, err := az.isCurrentInstance(name)
+		computeMetadata, err := az.getComputeMetadata()
+		if err != nil {
+			return "", err
+		}
+
+		isLocalInstance, err := az.isCurrentInstance(name, computeMetadata.Name)
 		if err != nil {
 			return "", err
 		}
@@ -160,11 +177,7 @@ func (az *Cloud) InstanceID(ctx context.Context, name types.NodeName) (string, e
 		}
 
 		// Get scale set name and instanceID from vmName for vmss.
-		metadataName, err := az.metadata.Text("instance/compute/name")
+		ssName, instanceID, err := extractVmssVMName(computeMetadata.Name)
-		if err != nil {
-			return "", err
-		}
-		ssName, instanceID, err := extractVmssVMName(metadataName)
 		if err != nil {
 			if err == ErrorNotVmssInstance {
 				// Compose machineID for standard Node.
@@ -197,14 +210,18 @@ func (az *Cloud) InstanceTypeByProviderID(ctx context.Context, providerID string
 //       Adding node label from cloud provider: beta.kubernetes.io/instance-type=[value]
 func (az *Cloud) InstanceType(ctx context.Context, name types.NodeName) (string, error) {
 	if az.UseInstanceMetadata {
-		isLocalInstance, err := az.isCurrentInstance(name)
+		computeMetadata, err := az.getComputeMetadata()
+		if err != nil {
+			return "", err
+		}
+
+		isLocalInstance, err := az.isCurrentInstance(name, computeMetadata.Name)
 		if err != nil {
 			return "", err
 		}
 		if isLocalInstance {
-			machineType, err := az.metadata.Text("instance/compute/vmSize")
+			if computeMetadata.VMSize != "" {
-			if err == nil {
+				return computeMetadata.VMSize, nil
-				return machineType, nil
 			}
 		}
 	}

pkg/cloudprovider/providers/azure/azure_zones.go

@@ -29,8 +29,8 @@ import (
 )
 
 const (
-	faultDomainURI  = "v1/InstanceInfo/FD"
+	faultDomainURI     = "v1/InstanceInfo/FD"
-	zoneMetadataURI = "instance/compute/zone"
+	computeMetadataURI = "instance/compute"
 )
 
 var faultMutex = &sync.Mutex{}
@@ -58,19 +58,20 @@ func (az *Cloud) GetZoneID(zoneLabel string) string {
 // GetZone returns the Zone containing the current availability zone and locality region that the program is running in.
 // If the node is not running with availability zones, then it will fall back to fault domain.
 func (az *Cloud) GetZone(ctx context.Context) (cloudprovider.Zone, error) {
-	zone, err := az.metadata.Text(zoneMetadataURI)
+	computeInfo := ComputeMetadata{}
+	err := az.metadata.Object(computeMetadataURI, &computeInfo)
 	if err != nil {
 		return cloudprovider.Zone{}, err
 	}
 
-	if zone == "" {
+	if computeInfo.Zone == "" {
 		glog.V(3).Infof("Availability zone is not enabled for the node, falling back to fault domain")
 		return az.getZoneFromFaultDomain()
 	}
 
-	zoneID, err := strconv.Atoi(zone)
+	zoneID, err := strconv.Atoi(computeInfo.Zone)
 	if err != nil {
-		return cloudprovider.Zone{}, fmt.Errorf("failed to parse zone ID %q: %v", zone, err)
+		return cloudprovider.Zone{}, fmt.Errorf("failed to parse zone ID %q: %v", computeInfo.Zone, err)
 	}
 
 	return cloudprovider.Zone{