Azure Instance Metadata Service – public preview
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 | Microsoft Azure operated by 21Vianet | Azure Stack Hub |
|---|---|---|
| azEnvironment | AZURECHINACLOUD | 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"