enabled instance metadata service by default (#1763)

Author: jackfrancis

docs/clusterdefinition.md

@@ -41,6 +41,7 @@ Here are the valid values for the orchestrator types:
 |maxPods|no|The maximum number of pods per node. The minimum valid value, necessary for running kube-system pods, is 5. Default value is 30 when networkPolicy equals azure, 110 otherwise.|
 |gcHighThreshold|no|Sets the --image-gc-high-threshold value on the kublet configuration. Default is 85. [See kubelet Garbage Collection](https://kubernetes.io/docs/concepts/cluster-administration/kubelet-garbage-collection/) |
 |gcLowThreshold|no|Sets the --image-gc-low-threshold value on the kublet configuration. Default is 80. [See kubelet Garbage Collection](https://kubernetes.io/docs/concepts/cluster-administration/kubelet-garbage-collection/) |
+|useInstanceMetadata|no|Use the Azure cloudprovider instance metadata service for appropriate resource discovery operations. Default is `true`.|
 |disabledAddons.dashboard|no|Disable dashboard addon (boolean - default == false, i.e. not disabled)|
 
 ### masterProfile

pkg/acsengine/engine.go

@@ -788,7 +788,12 @@ func (t *TemplateGenerator) getTemplateFuncMap(cs *api.ContainerService) templat
 			return cs.Properties.OrchestratorProfile.KubernetesConfig.UseManagedIdentity
 		},
 		"UseInstanceMetadata": func() bool {
-			return cs.Properties.OrchestratorProfile.KubernetesConfig.UseInstanceMetadata
+			if cs.Properties.OrchestratorProfile.KubernetesConfig.UseInstanceMetadata == nil {
+				return true
+			} else if *cs.Properties.OrchestratorProfile.KubernetesConfig.UseInstanceMetadata {
+				return true
+			}
+			return false
 		},
 		"GetVNETSubnetDependencies": func() string {
 			return getVNETSubnetDependencies(cs.Properties)

pkg/api/types.go

@@ -186,7 +186,7 @@ type KubernetesConfig struct {
 	CloudProviderRateLimitBucket     int            `json:"cloudProviderRateLimitBucket,omitempty"`
 	UseManagedIdentity               bool           `json:"useManagedIdentity,omitempty"`
 	CustomHyperkubeImage             string         `json:"customHyperkubeImage,omitempty"`
-	UseInstanceMetadata              bool           `json:"useInstanceMetadata,omitempty"`
+	UseInstanceMetadata              *bool          `json:"useInstanceMetadata,omitempty"`
 	EnableRbac                       bool           `json:"enableRbac,omitempty"`
 	EnableAggregatedAPIs             bool           `json:"enableAggregatedAPIs,omitempty"`
 	GCHighThreshold                  int            `json:"gchighthreshold,omitempty"`

pkg/api/vlabs/types.go

@@ -204,7 +204,7 @@ type KubernetesConfig struct {
 	CloudProviderRateLimitBucket     int            `json:"cloudProviderRateLimitBucket,omitempty"`
 	UseManagedIdentity               bool           `json:"useManagedIdentity,omitempty"`
 	CustomHyperkubeImage             string         `json:"customHyperkubeImage,omitempty"`
-	UseInstanceMetadata              bool           `json:"useInstanceMetadata,omitempty"`
+	UseInstanceMetadata              *bool          `json:"useInstanceMetadata,omitempty"`
 	EnableRbac                       bool           `json:"enableRbac,omitempty"`
 	EnableAggregatedAPIs             bool           `json:"enableAggregatedAPIs,omitempty"`
 	GCHighThreshold                  int            `json:"gchighthreshold,omitempty"`