Remove a VM association from a Capacity Reservation group

This article walks you through the steps of removing a VM association to a Capacity Reservation group. To learn more about capacity reservations, see the overview article.

Because both the VM and the underlying Capacity Reservation logically occupy capacity, Azure imposes some constraints on this process to avoid ambiguous allocation states and unexpected errors.

There are two ways to change an association:

• Option 1: Deallocate the virtual machine, change the Capacity Reservation group property, and optionally restart the virtual machine
• Option 2: Update the reserved quantity to zero and then change the Capacity Reservation group property

Deallocate the VM

The first option is to deallocate the VM, change the Capacity Reservation group property, and optionally restart the VM.

API

1. Deallocate the VM

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

2. Update the VM to remove association with the Capacity Reservation group

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

   In the request body, set the capacityReservationGroup property to null to remove the VM association to the group:

    {
   "location": "eastus",
   "properties": {
       "capacityReservation": {
           "capacityReservationGroup": {
               "id":null
           }
       }
   }
   }
   

Portal

1. Open Azure portal
2. Go to your VM and select Overview
3. Select Stop
   1. You will know your VM is deallocated when the status changes to Stopped (deallocated)
   2. At this point in the process, the VM is still associated with the Capacity Reservation group, which is reflected in the virtualMachinesAssociated property of the Capacity Reservation
4. Select Configuration
5. Set the Capacity Reservation group value to None
   • The VM is no longer associated with the Capacity Reservation group

CLI

1. Deallocate the virtual machine

   az vm deallocate 
   -g myResourceGroup 
   -n myVM
   

   Once the status changes to Stopped (deallocated), the virtual machine is deallocated.

2. Update the VM to remove association with the Capacity Reservation group by setting the capacity-reservation-group property to None:

   az vm update 
   -g myresourcegroup 
   -n myVM 
   --capacity-reservation-group None
   

PowerShell

1. Deallocate the virtual machine

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

   Once the status changes to Stopped (deallocated), the virtual machine is deallocated.

2. Update the VM to remove association with the Capacity Reservation group by setting the CapacityReservationGroupId property to null:

   $VirtualMachine =
   Get-AzVM
   -ResourceGroupName "myResourceGroup"
   -Name "myVM"
   
   Update-AzVM
   -ResourceGroupName "myResourceGroup"
   -VM $VirtualMachine
   -CapacityReservationGroupId $null
   

To learn more, go to Azure PowerShell commands Stop-AzVM, Get-AzVM, and Update-AzVM.

Update the reserved quantity to zero

The second option involves updating the reserved quantity to zero and then changing the Capacity Reservation group property.

This option works well when the virtual machine can’t be deallocated and when a reservation is no longer needed. For example, you may create a Capacity Reservation to temporarily assure capacity during a large-scale deployment. Once completed, the reservation is no longer needed.

API

1. Update the reserved quantity to zero

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

   In the request body, include the following parameters:

   {
   "sku":
       {
       "capacity": 0
       }
   }
   

   Note that capacity property is set to 0.

2. Update the VM to remove the association with the Capacity Reservation group

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

   In the request body, set the capacityReservationGroup property to null to remove the association:

   {
   "location": "eastus",
   "properties": {
       "capacityReservation": {
           "capacityReservationGroup": {
               "id":null
           }
       }
   }
   } 
   

Portal

1. Open Azure portal
2. Go to your Capacity Reservation group and select Overview
3. Select Reservations
4. Select Manage Reservation at the top of the page
5. On the Manage Reservations blade:
   1. Enter 0 in the Instances field
   2. Select Save
6. Go to your VM and select Configuration
7. Set the Capacity Reservation group value to None
   • Note that the VM is no longer associated with the Capacity Reservation group

CLI

1. Update reserved quantity to zero

   az capacity reservation update 
   -g myResourceGroup
   -c myCapacityReservationGroup 
   -n myCapacityReservation 
   --capacity 0
   

2. Update the VM to remove association with the Capacity Reservation group by setting the capacity-reservation-group property to None:

   az vm update 
   -g myresourcegroup 
   -n myVM 
   --capacity-reservation-group None
   

PowerShell

1. Update reserved quantity to zero

   Update-AzCapacityReservation
   -ResourceGroupName "myResourceGroup"
   -ReservationGroupName "myCapacityReservationGroup"
   -Name "myCapacityReservation"
   -CapacityToReserve 0
   

2. Update the VM to remove association with the Capacity Reservation group by setting the CapacityReservationGroupId property to null:

   $VirtualMachine =
   Get-AzVM
   -ResourceGroupName "myResourceGroup"
   -Name "myVM"
   
   Update-AzVM
   -ResourceGroupName "myResourceGroup"
   -VM $VirtualMachine
   -CapacityReservationGroupId $null
   

To learn more, go to Azure PowerShell commands New-AzCapacityReservation, Get-AzVM, and Update-AzVM.

Next steps

Learn how to associate a scale set to a Capacity Reservation group