Add initial support for the Azure instance metadata service.

pkg/cloudprovider/providers/azure/BUILD

@@ -15,6 +15,7 @@ go_library(
         "azure_backoff.go",
         "azure_blob.go",
         "azure_file.go",
+        "azure_instance_metadata.go",
         "azure_instances.go",
         "azure_loadbalancer.go",
         "azure_routes.go",

pkg/cloudprovider/providers/azure/azure.go

@@ -96,6 +96,9 @@ type Config struct {
 	CloudProviderRateLimitQPS float32 `json:"cloudProviderRateLimitQPS" yaml:"cloudProviderRateLimitQPS"`
 	// Rate limit Bucket Size
 	CloudProviderRateLimitBucket int `json:"cloudProviderRateLimitBucket" yaml:"cloudProviderRateLimitBucket"`
+
+	// Use instance metadata service where possible
+	UseInstanceMetadata bool `json:"useInstanceMetadata" yaml:"useInstanceMetadata"`
 }
 
 // Cloud holds the config and clients

pkg/cloudprovider/providers/azure/azure_instance_metadata.go

+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package azure
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+)
+
+// This is just for tests injection
+var metadataURL = "http://169.254.169.254/metadata"
+
+// SetMetadataURLForTesting is used to modify the URL used for
+// accessing the metadata server. Should only be used for testing!
+func SetMetadataURLForTesting(url string) {
+	metadataURL = url
+}
+
+// NetworkMetadata contains metadata about an instance's network
+type NetworkMetadata struct {
+	Interface []NetworkInterface `json:"interface"`
+}
+
+// NetworkInterface represents an instances network interface.
+type NetworkInterface struct {
+	IPV4 NetworkData `json:"ipv4"`
+	IPV6 NetworkData `json:"ipv6"`
+	MAC  string      `json:"macAddress"`
+}
+
+// NetworkData contains IP information for a network.
+type NetworkData struct {
+	IPAddress []IPAddress `json:"ipAddress"`
+	Subnet    []Subnet    `json:"subnet"`
+}
+
+// IPAddress represents IP address information.
+type IPAddress struct {
+	PrivateIP string `json:"privateIPAddress"`
+	PublicIP  string `json:"publicIPAddress"`
+}
+
+// Subnet represents subnet information.
+type Subnet struct {
+	Address string `json:"address"`
+	Prefix  string `json:"prefix"`
+}
+
+// QueryMetadataJSON queries the metadata server and populates the passed in object
+func QueryMetadataJSON(path string, obj interface{}) error {
+	data, err := queryMetadataBytes(path, "json")
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(data, obj)
+}
+
+// QueryMetadataText queries the metadata server and returns the corresponding text
+func QueryMetadataText(path string) (string, error) {
+	data, err := queryMetadataBytes(path, "text")
+	if err != nil {
+		return "", err
+	}
+	return string(data), err
+}
+
+func queryMetadataBytes(path, format string) ([]byte, error) {
+	client := &http.Client{}
+
+	req, err := http.NewRequest("GET", metadataURL+path, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Add("Metadata", "True")
+
+	q := req.URL.Query()
+	q.Add("format", format)
+	q.Add("api-version", "2017-04-02")
+	req.URL.RawQuery = q.Encode()
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	return ioutil.ReadAll(resp.Body)
+}

pkg/cloudprovider/providers/azure/azure_instances.go

@@ -29,6 +29,16 @@ import (
 
 // NodeAddresses returns the addresses of the specified instance.
 func (az *Cloud) NodeAddresses(name types.NodeName) ([]v1.NodeAddress, error) {
+	if az.UseInstanceMetadata {
+		text, err := QueryMetadataText("instance/network/interface/0/ipv4/ipAddress/0/privateIpAddress")
+		if err != nil {
+			return nil, err
+		}
+		return []v1.NodeAddress{
+			{Type: v1.NodeInternalIP, Address: text},
+			{Type: v1.NodeHostName, Address: string(name)},
+		}, nil
+	}
 	ip, err := az.getIPForMachine(name)
 	if err != nil {
 		glog.Errorf("error: az.NodeAddresses, az.getIPForMachine(%s), err=%v", name, err)

pkg/cloudprovider/providers/azure/azure_test.go

@@ -17,7 +17,11 @@ limitations under the License.
 package azure
 
 import (
+	"encoding/json"
 	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -801,3 +805,60 @@ func TestSplitProviderID(t *testing.T) {
 
 	}
 }
+
+func TestMetadataParsing(t *testing.T) {
+	data := `
+{
+    "interface": [
+      {
+        "ipv4": {
+          "ipAddress": [
+            {
+              "privateIpAddress": "10.0.1.4",
+              "publicIpAddress": "X.X.X.X"
+            }
+          ],
+          "subnet": [
+            {
+              "address": "10.0.1.0",
+              "prefix": "24"
+            }
+          ]
+        },
+        "ipv6": {
+          "ipAddress": [
+
+          ]
+        },
+        "macAddress": "002248020E1E"
+      }
+    ]
+}	
+`
+
+	network := NetworkMetadata{}
+	if err := json.Unmarshal([]byte(data), &network); err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	ip := network.Interface[0].IPV4.IPAddress[0].PrivateIP
+	if ip != "10.0.1.4" {
+		t.Errorf("Unexpected value: %s, expected 10.0.1.4", ip)
+	}
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, data)
+	}))
+	defer server.Close()
+
+	SetMetadataURLForTesting(server.URL)
+
+	networkJSON := NetworkMetadata{}
+	if err := QueryMetadataJSON("/some/path", &networkJSON); err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if !reflect.DeepEqual(network, networkJSON) {
+		t.Errorf("Unexpected inequality:\n%#v\nvs\n%#v", network, networkJSON)
+	}
+}