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Deploy Azure Spot Virtual Machines using Azure PowerShell

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

Using Azure Spot Virtual Machines allows you to take advantage of our unused capacity at a significant cost savings. At any point in time when Azure needs the capacity back, the Azure infrastructure will evict Azure Spot Virtual Machines. Therefore, Azure Spot Virtual Machines are great for workloads that can handle interruptions like batch processing jobs, dev/test environments, large compute workloads, and more.

Pricing for Azure Spot Virtual Machines is variable, based on region and SKU. For more information, see VM pricing for Linux and Windows. For more information about setting the max price, see Azure Spot Virtual Machines - Pricing.

You have option to set a max price you are willing to pay, per hour, for the VM. The max price for an Azure Spot Virtual Machine can be set in US dollars (USD), using up to 5 decimal places. For example, the value 0.98765would be a max price of $0.98765 USD per hour. If you set the max price to be -1, the VM won't be evicted based on price. The price for the VM will be the current price for spot or the price for a standard VM, which ever is less, as long as there is capacity and quota available.

Create the VM

Create a spotVM using New-AzVmConfig to create the configuration. Include -Priority Spot and set -MaxPrice to either:

  • -1 so the VM is not evicted based on price.
  • a dollar amount, up to 5 digits. For example, -MaxPrice .98765 means that the VM will be deallocated once the price for a spotVM goes about $.98765 per hour.

This example creates a spotVM that will not be deallocated based on pricing (only when Azure needs the capacity back). The eviction policy is set to deallocate the VM, so that it can be restarted at a later time. If you want to delete the VM and the underlying disk when the VM is evicted, set -EvictionPolicy to Delete in New-AzVMConfig.

$resourceGroup = "mySpotRG"
$location = "eastus"
$vmName = "mySpotVM"
$cred = Get-Credential -Message "Enter a username and password for the virtual machine."
New-AzResourceGroup -Name $resourceGroup -Location $location
$subnetConfig = New-AzVirtualNetworkSubnetConfig `
   -Name mySubnet -AddressPrefix 192.168.1.0/24
$vnet = New-AzVirtualNetwork -ResourceGroupName $resourceGroup `
   -Location $location -Name MYvNET -AddressPrefix 192.168.0.0/16 `
   -Subnet $subnetConfig
$pip = New-AzPublicIpAddress -ResourceGroupName $resourceGroup -Location $location `
  -Name "mypublicdns$(Get-Random)" -AllocationMethod Static -IdleTimeoutInMinutes 4
$nsgRuleRDP = New-AzNetworkSecurityRuleConfig -Name myNetworkSecurityGroupRuleRDP  -Protocol Tcp `
  -Direction Inbound -Priority 1000 -SourceAddressPrefix * -SourcePortRange * -DestinationAddressPrefix * `
  -DestinationPortRange 3389 -Access Deny
$nsg = New-AzNetworkSecurityGroup -ResourceGroupName $resourceGroup -Location $location `
  -Name myNetworkSecurityGroup -SecurityRules $nsgRuleRDP
$nic = New-AzNetworkInterface -Name myNic -ResourceGroupName $resourceGroup -Location $location `
  -SubnetId $vnet.Subnets[0].Id -PublicIpAddressId $pip.Id -NetworkSecurityGroupId $nsg.Id

# Create a virtual machine configuration and set this to be an Azure Spot Virtual Machine

$vmConfig = New-AzVMConfig -VMName $vmName -VMSize Standard_D1 -Priority "Spot" -MaxPrice -1 -EvictionPolicy Deallocate | `
Set-AzVMOperatingSystem -Windows -ComputerName $vmName -Credential $cred | `
Set-AzVMSourceImage -PublisherName MicrosoftWindowsServer -Offer WindowsServer -Skus 2016-Datacenter -Version latest | `
Add-AzVMNetworkInterface -Id $nic.Id

New-AzVM -ResourceGroupName $resourceGroup -Location $location -VM $vmConfig

After the VM is created, you can query to see the max price for all of the VMs in the resource group.

Get-AzVM -ResourceGroupName $resourceGroup | `
   Select-Object Name,@{Name="maxPrice"; Expression={$_.BillingProfile.MaxPrice}}

Simulate an eviction

You can simulate an eviction of an Azure Spot Virtual Machine using REST, PowerShell, or the CLI, to test how well your application will respond to a sudden eviction.

In most cases, you will want to use the REST API Virtual Machines - Simulate Eviction to help with automated testing of applications. For REST, a Response Code: 204 means the simulated eviction was successful. You can combine simulated evictions with the Scheduled Event service, to automate how your app will respond when the VM is evicted.

To see scheduled events in action, watch Azure Friday - Using Azure Scheduled Events to prepare for VM maintenance.

Quick test

For a quick test to show how a simulated eviction will work, let's walk through querying the scheduled event service to see what it looks like when you simulate an eviction using PowerShell.

The Scheduled Event service is enabled for your service the first time you make a request for events.

Remote into your VM, and then open a command prompt.

From the command prompt on your VM, type:

curl -H Metadata:true http://169.254.169.254/metadata/scheduledevents?api-version=2019-08-01

This first response could take up to 2 minutes. From now on, they should display output almost immediately.

From a computer that has the Az PowerShell module installed (like your local machine), simulate an eviction using Set-AzVM. Replace the resource group name and VM name with your own.

Set-AzVM -ResourceGroupName "mySpotRG" -Name "mySpotVM" -SimulateEviction

The response output will have Status: Succeeded if the request was successfully made.

Quickly go back to your remote connection to your Spot Virtual Machine and query the Scheduled Events endpoint again. Repeat the following command until you get an output that contains more information:

curl -H Metadata:true http://169.254.169.254/metadata/scheduledevents?api-version=2019-08-01

When the Scheduled Event Service gets the eviction notification, you will get a response that looks similar to this:

{"DocumentIncarnation":1,"Events":[{"EventId":"A123BC45-1234-5678-AB90-ABCDEF123456","EventStatus":"Scheduled","EventType":"Preempt","ResourceType":"VirtualMachine","Resources":["myspotvm"],"NotBefore":"Tue, 16 Mar 2021 00:58:46 GMT","Description":"","EventSource":"Platform"}]}

You can see that "EventType":"Preempt", and the resource is the VM resource "Resources":["myspotvm"].

You can also see when the VM will be evicted by checking the "NotBefore" value. The VM will not be evicted before the time given in NotBefore, so that is your window for your application to gracefully close out.

Next steps

You can also create an Azure Spot Virtual Machine using the Azure CLI, portal or a template.

Query current pricing information using the Azure retail prices API for information about Azure Spot Virtual Machine pricing. The meterName and skuName will both contain Spot.

If you encounter an error, see Error codes.