Associate a VM to a capacity reservation group

Applies to: ✔️ Windows Virtual Machines ✔️ Linux Virtual Machines

You can use capacity reservation groups with new or existing virtual machines (VMs). To learn more about capacity reservations, see the Capacity reservation overview.

Associate a new virtual machine

To associate a new virtual machine to the capacity reservation group, the group must be explicitly referenced as a property of the VM. This reference protects the matching reservation in the group for applications and workloads intended to use it.

API

To add the capacityReservationGroup property to a VM, construct the following PUT request to the Microsoft.Compute provider:

PUT https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachines/{VirtualMachineName}?api-version=2021-04-01

In the request body, include the capacityReservationGroup property:

{ 
  "location": "eastus", 
  "properties": { 
    "hardwareProfile": { 
      "vmSize": "Standard_D2s_v3" 
    }, 
    … 
   "capacityReservation":{ 
    "capacityReservationGroup":{ 
        "id":"subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/CapacityReservationGroups/{CapacityReservationGroupName}" 
    } 
    "storageProfile": { 
    … 
    }, 
    "osProfile": { 
    … 
    }, 
    "networkProfile": { 
     …     
    } 
  } 
} 

Portal

1. Open the Azure portal.
2. In the search bar, enter virtual machine.
3. Under Services, select Virtual machines.
4. On the Virtual machines page, select Create and then select Virtual machine.
5. On the Basics tab, under Project details, select the correct subscription. Then choose to create a new resource group or use an existing one.
6. Under Instance details, enter the VM name and choose your region.
7. Select an Image and the VM size.
8. Under Administrator account, enter a username and a password. The password must be at least 12 characters long and meet the defined complexity requirements.
9. Go to the Advanced section.
10. In the Capacity Reservations dropdown list, select the capacity reservation group that you want to associate to the VM.
11. Select Review + create.
12. After validation runs, select Create.
13. After the deployment is finished, select Go to resource.

CLI

Use az vm create to create a new VM and add the capacity-reservation-group property to associate it to an existing capacity reservation group. The following example creates a Standard_D2s_v3 VM in the East US location and associates the VM to a capacity reservation group.

az vm create 
--resource-group myResourceGroup 
--name myVM 
--location eastus 
--size Standard_D2s_v3 
--image Ubuntu2204 
--capacity-reservation-group /subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{capacityReservationGroupName}

PowerShell

Use New-AzVM to create a new VM and add the CapacityReservationGroupId property to associate it to an existing capacity reservation group. The following example creates a Standard_D2s_v3 VM in the East US location and associates the VM to a capacity reservation group.

New-AzVm
-ResourceGroupName "myResourceGroup"
-Name "myVM"
-Location "eastus"
-VirtualNetworkName "myVnet"
-SubnetName "mySubnet"
-SecurityGroupName "myNetworkSecurityGroup"
-PublicIpAddressName "myPublicIpAddress"
-Size "Standard_D2s_v3"
-CapacityReservationGroupId "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{capacityReservationGroupName}"

To learn more, see the Azure PowerShell command New-AzVM.

ARM template

An Azure Resource Manager template (ARM template) is a JavaScript Object Notation (JSON) file that defines the infrastructure and configuration for your project. The template uses declarative syntax. In declarative syntax, you describe your intended deployment without writing the sequence of programming commands to create the deployment.

ARM templates let you deploy groups of related resources. In a single template, you can create a capacity reservation group and capacity reservations. You can deploy templates through the Azure portal, the Azure CLI, or Azure PowerShell, or from continuous integration/continuous delivery (CI/CD) pipelines.

Associate an existing virtual machine

For the initial release of a capacity reservation, a virtual machine must be allocated to a capacity reservation:

1. Follow guidance to create a capacity reservation group and capacity reservation, if necessary. Or increment the quantity of an existing capacity reservation so there's unused reserved capacity.
2. Deallocate the virtual machine.
3. Update the capacity reservation group property on the VM.
4. Restart the VM.

Follow the steps to associate the virtual machine to a capacity reservation group.

API

1. Deallocate the virtual machine:

   PUT https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourcegroupname}/providers/Microsoft.Compute/virtualMachines/{VirtualMachineName}/deallocate?api-version=2021-04-01
   

2. Add the capacityReservationGroup property to the VM. Construct the following PUT request to Microsoft.Compute provider:

   PUT https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachines/{VirtualMachineName}?api-version=2021-04-01
   

   In the request body, include the capacityReservationGroup property:

   {
   "location": "eastus",
   "properties": {
       "capacityReservation": {
           "capacityReservationGroup": {
               "id": "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{capacityReservationGroupName}"
           }
       }
   }
   }
   

Portal

1. Open the Azure portal.
2. Go to your VM.
3. Select Overview.
4. Select Stop at the top of the page to deallocate the VM.
5. Go to Configurations on the left.
6. In the Capacity Reservation group dropdown list, select the group that you want to associate to the VM.

CLI

1. Deallocate the virtual machine:

   az vm deallocate 
   -g myResourceGroup 
   -n myVM
   

2. Associate the VM to a capacity reservation group:

   az vm update 
   -g myresourcegroup 
   -n myVM 
   --capacity-reservation-group subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{CapacityReservationGroupName}
   

PowerShell

1. Deallocate the virtual machine:

   Stop-AzVM
   -ResourceGroupName "myResourceGroup"
   -Name "myVM"
   

2. Associate the VM to a capacity reservation group:

   $VirtualMachine =
   Get-AzVM
   -ResourceGroupName "myResourceGroup"
   -Name "myVM"
   
   Update-AzVM
   -ResourceGroupName "myResourceGroup"
   -VM $VirtualMachine
   -CapacityReservationGroupId "subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{CapacityReservationGroupName}"
   

To learn more, see the Azure PowerShell commands Stop-AzVM, Get-AzVM, and Update-AzVM.

View VM association with the Instance View

After the capacityReservationGroup property is set, an association now exists between the VM and the group. Azure automatically finds the matching capacity reservation in the group and consumes a reserved slot. The capacity reservation's Instance View reflects the new VM in the virtualMachinesAllocated property:

API

GET https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/CapacityReservationGroups/{capacityReservationGroupName}?$expand=instanceView&api-version=2021-04-01 

{
   "name":"{CapacityReservationGroupName}",
   "id":"/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{CapacityReservationGroupName}",
   "type":"Microsoft.Compute/capacityReservationGroups",
   "location":"eastus",
   "properties":{
      "capacityReservations":[
         {
            "id":"/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/ {CapacityReservationGroupName}/capacityReservations/{CapacityReservationName}"
         }
      ],
      "virtualMachinesAssociated":[
         {
            "id":"/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachines/{myVM}"
         }
      ],
      "instanceView":{
         "capacityReservations":[
            {
               "name":"{CapacityReservationName}",
               "utilizationInfo":{
                  "virtualMachinesAllocated":[
                     {
                        "id":"/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachines/{myVM}"
                     }
                  ]
               },
               "statuses":[
                  {
                     "code":"ProvisioningState/succeeded",
                     "level":"Info",
                     "displayStatus":"Provisioning succeeded",
                     "time":"2021-05-25T15:12:10.4165243+00:00"
                  }
               ]
            }
         ]
      }
   }
} 

CLI

az capacity reservation show 
-g myResourceGroup
-c myCapacityReservationGroup 
-n myCapacityReservation 

PowerShell

$CapRes=
Get-AzCapacityReservation
-ResourceGroupName <"ResourceGroupName">
-ReservationGroupName] <"CapacityReservationGroupName">
-Name <"CapacityReservationName">
-InstanceView

$CapRes.InstanceView.Utilizationinfo.VirtualMachinesAllocated

To learn more, see the Azure PowerShell command Get-AzCapacityReservation.

Portal

1. Open the Azure portal.
2. Go to your capacity reservation group.
3. Under Settings on the left, select Resources.
4. Look at the table to see all the VMs that are associated to the capacity reservation group.

Next step

Remove a VM's association to a capacity reservation group