Create a capacity reservation

Applies to: ✔️ Linux VMs ✔️ Windows VMs ✔️ Uniform scale set ✔️ Flexible scale sets

Capacity reservation is always created as part of a capacity reservation group. The first step is to create a group if a suitable one doesn't exist already, and then create reservations. After reservations are successfully created, they're immediately available for use with virtual machines (VMs). The capacity is reserved for your use as long as the reservation isn't deleted.

A well-formed request for a capacity reservation group should always succeed because it doesn't reserve any capacity. It just acts as a container for reservations. However, a request for capacity reservation could fail if you don't have the required quota for the VM series or if Azure doesn't have enough capacity to fulfill the request. Either request more quota or try a different VM size, location, or zone combination.

Capacity reservation creation succeeds or fails in its entirety. For a request to reserve 10 instances, success is returned only if all 10 instances could be allocated. Otherwise, the capacity reservation creation fails.

Considerations

The capacity reservation must meet the following rules:

• The location parameter must match the location property for the parent capacity reservation group. A mismatch results in an error.
• The VM size must be available in the target region. Otherwise, the reservation creation fails.
• The subscription must have available quota equal to or more than the quantity of VMs being reserved for the VM series and for the region overall. If needed, request more quota.
  • As needed to satisfy existing quota limits, you can do single VMs in stages. Create a capacity reservation with a smaller quantity and reallocate that quantity of VMs. This approach frees up quota to increase the quantity reserved and add more VMs. Alternatively, if the subscription uses different VM sizes in the same series, reserve and redeploy VMs for the first size. Then add a reservation to the group for another size and redeploy the VMs for the new size to the reservation group. Repeat the process until it's complete.
  • For scale sets, available quota is required unless the scale set or you delete its VM instances, capacity is reserved, and the scale set instances are added by using reserved capacity. If the scale set is updated by using blue green deployment, then reserve the capacity and deploy the new scale set to the reserved capacity at the next update.
• Each capacity reservation group can have exactly one reservation for a specific VM size. For example, you can create only one capacity reservation for the VM size Standard_D2s_v3. Attempting to create a second reservation for Standard_D2s_v3 in the same capacity reservation group results in an error. However, you can create another reservation in the same group for other VM sizes, such as Standard_D4s_v3 and Standard_D8s_v3.
• For a capacity reservation group that supports zones, each reservation type is defined by the combination of VM size and zone. For example, one capacity reservation for Standard_D2s_v3 in Zone 1, another capacity reservation for Standard_D2s_v3 in Zone 2, and a third capacity reservation for Standard_D2s_v3 in Zone 3 are supported.

Check VM sizes that are available for capacity reservation in a region

Before you create a capacity reservation, you can check the VM sizes that are available for the reservation for a particular region.

Portal

1. Open the Azure portal.
2. In the search bar, enter capacity reservation groups.
3. Select Capacity reservation groups from the options.
4. Select Create.
5. On the Basics tab, create a capacity reservation group:
   1. Select a Subscription.
   2. Select or create a resource group.
   3. Name your group.
   4. Select a region.
   5. Optionally, select Availability zones or allow Azure to choose for you.
6. Select Next.
7. On VM size, select See all sizes to check what VM sizes are available for capacity reservation.

CLI

Before you create a capacity reservation, you can check the reservation's available VM sizes for the region that you selected. The following example lists the capacity reservation VM sizes that are available in the East US location by using the Azure CLI:

 az vm list-skus -l eastus --resource-type virtualMachines --query "[?contains(capabilities[?name == 'CapacityReservationSupported' && value == 'True'].name,'CapacityReservationSupported')].name"

PowerShell

Before you create a capacity reservation, you can check the capacity reservation VM sizes that are available for the region you selected by using Get-AzComputeResourceSku for the capability property for the resource type virtualMachines. The following example lists the capacity reservation VM sizes that are available in the East US location:

 $vmsizes = Get-AzComputeResourceSku -Location eastus | where {$_.ResourceType -eq "virtualMachines"}
 foreach($vmsize in $vmsizes) { foreach($capability in $vmsize.capabilities) {  if($capability.Name -eq 'CapacityReservationSupported' -and $capability.Value -eq 'true'){ $vmsize.name  } } }

Create a capacity reservation

API

1. Create a capacity reservation group.

   To create a capacity reservation group, construct the following PUT request on the Microsoft.Compute provider:

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

   In the request body, include the following parameter:

   { 
     "location":"eastus"
   } 
   

   This group is created to contain reservations for the US East location.

   The group in the following example only supports regional reservations because zones weren't specified at the time of creation. To create a zonal group, pass an extra parameter zone in the request body:

   { 
     "location":"eastus",
     "zones": ["1", "2", "3"] 
   } 
   

2. Create a capacity reservation.

   To create a reservation, construct the following PUT request on the Microsoft.Compute provider:

   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:

   { 
     "location": "eastus", 
     "sku": { 
       "name": "Standard_D2s_v3", 
       "capacity": 5 
     }, 
    "tags": { 
           "environment": "testing" 
   } 
   

   The preceding request creates a reservation in the East US location for five quantities of the D2s_v3 VM size.

Portal

1. Open the Azure portal.
2. In the search bar, enter capacity reservation groups.
3. Select Capacity reservation groups from the options.
4. Select Create.
5. On the Basics tab, create a capacity reservation group:
   1. Select a subscription.
   2. Select or create a resource group.
   3. Name your group.
   4. Select a region.
   5. Optionally, select Availability zones or allow Azure to choose for you.
6. Select Next.
7. On the Reservations tab, create at least one capacity reservation:
   1. Give each reservation a reservation name, the quantity of VM instances, and select a unique VM size.
   2. Billing information based on your selections appears in the Cost/month column.
8. Select Next.
9. On the Tags tab, optionally create tags.
10. Select Next.
11. On the Review + Create tab, review your capacity reservation group information.
12. Select Create.

CLI

1. Before you can create a capacity reservation, create a resource group with az group create. The following example creates a resource group myResourceGroup in the East US location.

   az group create 
   -l eastus 
   -g myResourceGroup
   

2. Now create a capacity reservation group with az capacity reservation group create. The following example creates a group myCapacityReservationGroup in the East US location for all three availability zones.

   az capacity reservation group create 
   -n myCapacityReservationGroup 
   -l eastus 
   -g myResourceGroup 
   --zones 1 2 3 
   

3. After the capacity reservation group is created, create a new capacity reservation with az capacity reservation create. The following example creates myCapacityReservation for five quantities of Standard_D2s_v3 VM size in Zone 1 of the East US location.

   az capacity reservation create 
   -c myCapacityReservationGroup 
   -n myCapacityReservation 
   -l eastus 
   -g myResourceGroup 
   --sku Standard_D2s_v3 
   --capacity 5 
   --zone 1
   

PowerShell

1. Before you can create a capacity reservation, create a resource group with New-AzResourceGroup. The following example creates a resource group myResourceGroup in the East US location.

   New-AzResourceGroup
   -ResourceGroupName "myResourceGroup"
   -Location "eastus"
   

2. Now create a capacity reservation group with New-AzCapacityReservationGroup. The following example creates a group myCapacityReservationGroup in the East US location for all three availability zones.

   New-AzCapacityReservationGroup
   -ResourceGroupName "myResourceGroup"
   -Location "eastus"
   -Zone "1","2","3"
   -Name "myCapacityReservationGroup"
   

3. After the capacity reservation group is created, create a new capacity reservation with New-AzCapacityReservation. The following example creates myCapacityReservation for five quantities of Standard_D2s_v3 VM size in Zone 1 of the East US location.

   New-AzCapacityReservation
   -ResourceGroupName "myResourceGroup"
   -Location "eastus"
   -Zone "1"
   -ReservationGroupName "myCapacityReservationGroup"
   -Name "myCapacityReservation"
   -Sku "Standard_D2s_v3"
   -CapacityToReserve 5
   

To learn more, see the Azure PowerShell commands New-AzResourceGroup, New-AzCapacityReservationGroup, and New-AzCapacityReservation.

ARM template

An Azure Resource Manager template (ARM template) is a 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.

Check on your capacity reservation

After the capacity reservation is successfully created, it's immediately available for use with VMs.

API

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

{ 
    "name": "<CapacityReservationName>", 
    "id": "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/capacityReservationGroups/{CapacityReservationGroupName}/capacityReservations/{CapacityReservationName}", 
    "type": "Microsoft.Compute/capacityReservationGroups/capacityReservations", 
    "location": "eastus", 
    "tags": { 
        "environment": "testing" 
    }, 
    "sku": { 
        "name": "Standard_D2s_v3", 
        "capacity": 5 
    }, 
    "properties": { 
        "reservationId": "<reservationId>", 
         "provisioningTime": "<provisioningTime>", 
         "provisioningState": "Updating" 
    } 
} 

CLI

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

PowerShell

Check on your capacity reservation:

Get-AzCapacityReservation
-ResourceGroupName <"ResourceGroupName">
-ReservationGroupName <"CapacityReservationGroupName">
-Name <"CapacityReservationName">

To find the VM size and the quantity reserved, use the following command:

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

$CapRes.sku

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

Portal

1. Open the Azure portal.
2. In the search bar, enter capacity reservation groups.
3. Select Capacity reservation groups from the options.
4. From the list, select the capacity reservation group name you created.
5. Select Overview.
6. Select Reservations.
7. In this view, you can see all the reservations in the group along with the VM size and quantity reserved.

Next step

Learn how to modify your capacity reservation