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Azure Instance Metadata Service – public preview

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The Azure Instance Metadata Service (IMDS) provides information about currently running virtual machine instances. You can use it to manage and configure your virtual machines. This information includes the SKU, storage, and network configurations. For a complete list of the data available, see the endpoint categories summary.

IMDS is available for running instances of virtual machines (VMs) and virtual machine scale set instances. All endpoints support VMs created and managed by using Azure Resource Manager.

IMDS is a REST API that's available at a well-known, non-routable IP address (169.254.169.254). You can only access it from within the VM. Communication between the VM and IMDS never leaves the host. You can have your HTTP clients bypass web proxies within the VM when querying IMDS, and treat 169.254.169.254 the same as 168.63.129.16.

Usage

To learn more about IMDS and how to use it, see the Azure Instance Metadata Service documentation. This article focuses on differences between Azure and Azure Stack Hub, as the service is in public preview.

Differences between Azure and Azure Stack Hub

Supported endpoint categories

The IMDS API contains multiple endpoint categories representing different data sources, each of which contains one or more endpoints. See each category for details.

Category root Description Available in Azure Stack Hub
/metadata/attested See Attested Data Not available
/metadata/identity See Managed Identity via IMDS Not available
/metadata/instance See Instance metadata Azure Stack Hub 1.2108.2.73
/metadata/loadbalancer See Retrieve Load Balancer metadata via IMDS Not available
/metadata/versions See Versions Azure Stack Hub 1.2108.2.73

Rest response

The following properties return either a different value or are expected to return nothing:

Property Azure Azure Stack Hub
azEnvironment AZUREPUBLICCLOUD AzureStack
customdata supported Not supported
plan supported Not supported
zone supported Not supported

Sample response:

{
  "compute":  {
          "azEnvironment":  "AzureStack",
          "customData":  "",
          "evictionPolicy":  "",
          "extendedLocation":  {
                          "name":  "",
                          "type":  ""
                        },
          "isHostCompatibilityLayerVm":  "",
          "licenseType":  "",
          "location":  "orlando",
          "name":  "IMDSVALI",
          "offer":  "WindowsServer",
          "osProfile":  {
                            "adminUsername":  "sampleuser",
                            "computerName":  "IMDSVALI",
                            "disablePasswordAuthentication":  ""
                        },
          "osType":  "Windows",
          "placementGroupId":  "",
          "plan":  {
                       "name":  "",
                       "product":  "",
                       "publisher":  ""
                   },
          "platformFaultDomain":  "0",
          "platformUpdateDomain":  "0",
          "priority":  "",
          "provider":  "Microsoft.Compute",
          "publicKeys":  [

                     ],
          "publisher":  "MicrosoftWindowsServer",
          "resourceGroupName":  "IMDS",
          "resourceId":  "/subscriptions/1cf1cb48-fad3-4872-9366-c5c51fe748e6/resourceGroups/IMDS/providers/Microsoft.Compute/virtualMachines/IMDSVALI",
          "securityProfile":  {
                                  "secureBootEnabled":  "",
                                  "virtualTpmEnabled":  ""
                              },
          "sku":  "2019-Datacenter",
          "storageProfile":  {
                                 "dataDisks":  [
                                                ],
                                 "imageReference":  {
                                                        "id":  "",
                                                        "offer":  "WindowsServer",
                                                        "publisher":  "MicrosoftWindowsServer",
                                                        "sku":  "2019-Datacenter",
                                                        "version":  "17763.2114.2108051826"
                                                    },
                                 "osDisk":  {
                                                "caching":  "ReadWrite",
                                                "createOption":  "FromImage",
                                                "diffDiskSettings":  {
                                                                         "option":  ""
                                                                     },
                                                "diskSizeGB":  "127",
                                                "encryptionSettings":  {
                                                                           "enabled":  "false"
                                                                       },
                                                "image":  {
                                                              "uri":  ""
                                                          },
                                                "managedDisk":  {
                                                                    "id":  "/subscriptions/1cf1cb48-fad3-4872-9366-c5c51fe748e6/resourceGroups/IMDS/providers/Mi
crosoft.Compute/disks/IMDSVALI_OsDisk_1_589d8d9cdd8a4c34a004b0dcecd68b05",
                                                                    "storageAccountType":  "Premium_LRS"
                                                                },
                                                "name":  "IMDSVALI_OsDisk_1_589d8d9cdd8a4c34a004b0dcecd68b05",
                                                "osType":  "Windows",
                                                "vhd":  {
                                                            "uri":  ""
                                                        },
                                                "writeAcceleratorEnabled":  "false"
                                            },
                                 "resourceDisk":  {
                                                      "size":  ""
                                                  }
                             },
          "subscriptionId":  "1cf1cb48-fad3-4872-9366-c5c51fe748e6",
          "tags":  "",
          "tagsList":  [

                       ],
          "userData":  "",
          "version":  "17763.2114.2108051826",
          "virtualMachineScaleSet":  {
                                         "id":  ""
                                     },
          "vmId":  "fa4fb8e6-265d-4d5f-98cd-20b0a68bc678",
          "vmScaleSetName":  "",
          "vmSize":  "Standard_DS1_v2",
          "zone":  ""
      },
"network":  {
            "interface":  [
                            {
                            "ipv4":  {
                                      "ipAddress":  [
                                                         {
                                                          "privateIpAddress":  "10.0.2.4",
                                                          "publicIpAddress":  "10.217.119.162"
                                                         }
                                                    ],
                                       "subnet":  [
                                                         {
                                                          "address":  "10.0.2.0",
                                                          "prefix":  "24"
                                                         }
                                                  ]
                                  },
                              "ipv6": {
                                       "ipAddress":  [

                                                     ]
                                      },
                              "macAddress":  "001DD8B700C3"
                              }
                          ]
            }
}

Supported API versions

  • "2017-03-01",
  • "2017-04-02",
  • "2017-08-01",
  • "2017-10-01",
  • "2017-12-01",
  • "2018-02-01",
  • "2018-04-02",
  • "2018-10-01",
  • "2019-02-01",
  • "2019-03-11",
  • "2019-04-30",
  • "2019-06-01",
  • "2019-06-04",
  • "2019-08-01",
  • "2019-08-15",
  • "2019-11-01",
  • "2020-06-01",
  • "2020-07-15",
  • "2020-09-01",
  • "2020-10-01",
  • "2020-12-01",
  • "2021-01-01",
  • "2021-02-01",
  • "2021-03-01",
  • "2021-05-01"