Tutorial: Create and manage a virtual machine scale set with Azure PowerShell
Applies to: ✔️ Linux VMs ✔️ Windows VMs ✔️ Uniform scale sets
A virtual machine scale set allows you to deploy and manage a set of identical, auto-scaling virtual machines. Throughout the lifecycle of a virtual machine scale set, you may need to run one or more management tasks. In this tutorial you learn how to:
- Create and connect to a virtual machine scale set
- Select and use VM images
- View and use specific VM instance sizes
- Manually scale a scale set
- Perform common scale set management tasks
If you don't have an Azure subscription, create a free account before you begin.
This article has been updated to use the Azure Az PowerShell module. The Az PowerShell module is the recommended PowerShell module for interacting with Azure. To get started with the Az PowerShell module, see Install Azure PowerShell. To learn how to migrate to the Az PowerShell module, see Migrate Azure PowerShell from AzureRM to Az.
Use Azure Cloud Shell
Azure hosts Azure Cloud Shell, an interactive shell environment that you can use through your browser. You can use either Bash or PowerShell with Cloud Shell to work with Azure services. You can use the Cloud Shell preinstalled commands to run the code in this article without having to install anything on your local environment.
To start Azure Cloud Shell:
|Select Try It in the upper-right corner of a code block. Selecting Try It doesn't automatically copy the code to Cloud Shell.|
|Go to https://shell.azure.com, or select the Launch Cloud Shell button to open Cloud Shell in your browser.|
|Select the Cloud Shell button on the menu bar at the upper right in the Azure portal.|
To run the code in this article in Azure Cloud Shell:
Start Cloud Shell.
Select the Copy button on a code block to copy the code.
Paste the code into the Cloud Shell session by selecting Ctrl+Shift+V on Windows and Linux or by selecting Cmd+Shift+V on macOS.
Select Enter to run the code.
Create a resource group
An Azure resource group is a logical container into which Azure resources are deployed and managed. A resource group must be created before a virtual machine scale set. Create a resource group with the New-AzResourceGroup command. In this example, a resource group named myResourceGroup is created in the EastUS region.
New-AzResourceGroup -ResourceGroupName "myResourceGroup" -Location "EastUS"
The resource group name is specified when you create or modify a scale set throughout this tutorial.
Create a scale set
First, set an administrator username and password for the VM instances with Get-Credential:
$cred = Get-Credential
Now create a virtual machine scale set with New-AzVmss. To distribute traffic to the individual VM instances, a load balancer is also created. The load balancer includes rules to distribute traffic on TCP port 80, as well as allow remote desktop traffic on TCP port 3389 and PowerShell remoting on TCP port 5985:
New-AzVmss ` -ResourceGroupName "myResourceGroup" ` -VMScaleSetName "myScaleSet" ` -Location "EastUS" ` -VirtualNetworkName "myVnet" ` -SubnetName "mySubnet" ` -PublicIpAddressName "myPublicIPAddress" ` -LoadBalancerName "myLoadBalancer" ` -Credential $cred
It takes a few minutes to create and configure all the scale set resources and VM instances.
If you are unable to connect to your scale set, you may need to create a Network Security Group by adding the -SecurityGroupName "mySecurityGroup" parameter.
View the VM instances in a scale set
To view a list of VM instances in a scale set, use Get-AzVmssVM as follows:
Get-AzVmssVM -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet"
The following example output shows two VM instances in the scale set:
ResourceGroupName Name Location Sku InstanceID ProvisioningState ----------------- ---- -------- --- ---------- ----------------- MYRESOURCEGROUP myScaleSet_0 eastus Standard_DS1_v2 0 Succeeded MYRESOURCEGROUP myScaleSet_1 eastus Standard_DS1_v2 1 Succeeded
To view additional information about a specific VM instance, add the
-InstanceId parameter to Get-AzVmssVM. The following example views information about VM instance 1:
Get-AzVmssVM -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet" -InstanceId "1"
List connection information
A public IP address is assigned to the load balancer that routes traffic to the individual VM instances. By default, Network Address Translation (NAT) rules are added to the Azure load balancer that forwards remote connection traffic to each VM on a given port. To connect to the VM instances in a scale set, you create a remote connection to an assigned public IP address and port number.
To list the NAT ports to connect to VM instances in a scale set, first get the load balancer object with Get-AzLoadBalancer. Then, view the inbound NAT rules with Get-AzLoadBalancerInboundNatRuleConfig:
# Get the load balancer object $lb = Get-AzLoadBalancer -ResourceGroupName "myResourceGroup" -Name "myLoadBalancer" # View the list of inbound NAT rules Get-AzLoadBalancerInboundNatRuleConfig -LoadBalancer $lb | Select-Object Name,Protocol,FrontEndPort,BackEndPort
The following example output shows the instance name, public IP address of the load balancer, and port number that the NAT rules forward traffic to:
Name Protocol FrontendPort BackendPort ---- -------- ------------ ----------- myScaleSet3389.0 Tcp 50001 3389 myScaleSet5985.0 Tcp 51001 5985 myScaleSet3389.1 Tcp 50002 3389 myScaleSet5985.1 Tcp 51002 5985
The Name of the rule aligns with the name of the VM instance as shown in a previous Get-AzVmssVM command. For example, to connect to VM instance 0, you use myScaleSet3389.0 and connect to port 50001. To connect to VM instance 1, use the value from myScaleSet3389.1 and connect to port 50002. To use PowerShell remoting, you connect to the appropriate VM instance rule for TCP port 5985.
View the public IP address of the load balancer with Get-AzPublicIpAddress:
Get-AzPublicIpAddress -ResourceGroupName "myResourceGroup" -Name "myPublicIPAddress" | Select IpAddress
IpAddress --------- 184.108.40.206
Create a remote connection to your first VM instance. Specify your public IP address and port number of the required VM instance, as shown from the preceding commands. When prompted, enter the credentials used when you created the scale set (by default in the sample commands, azureuser and P@ssw0rd!). If you use the Azure Cloud Shell, perform this step from a local PowerShell prompt or Remote Desktop Client. The following example connects to VM instance 1:
mstsc /v 220.127.116.11:50001
Once logged in to the VM instance, you could perform some manual configuration changes as needed. For now, close the remote connection.
Understand VM instance images
Azure marketplace includes many images that can be used to create VM instances. To see a list of available publishers, use the Get-AzVMImagePublisher command.
Get-AzVMImagePublisher -Location "EastUS"
To view a list of images for a given publisher, use Get-AzVMImageSku. The image list can also be filtered by
-Offer. In the following example, the list is filtered for all images with publisher name of MicrosoftWindowsServer and an offer that matches WindowsServer:
Get-AzVMImageSku -Location "EastUS" -PublisherName "MicrosoftWindowsServer" -Offer "WindowsServer"
The following example output shows all of the available Windows Server images:
Skus Offer PublisherName Location ---- ----- ------------- -------- 2008-R2-SP1 WindowsServer MicrosoftWindowsServer eastus 2008-R2-SP1-smalldisk WindowsServer MicrosoftWindowsServer eastus 2012-Datacenter WindowsServer MicrosoftWindowsServer eastus 2012-Datacenter-smalldisk WindowsServer MicrosoftWindowsServer eastus 2012-R2-Datacenter WindowsServer MicrosoftWindowsServer eastus 2012-R2-Datacenter-smalldisk WindowsServer MicrosoftWindowsServer eastus 2016-Datacenter WindowsServer MicrosoftWindowsServer eastus 2016-Datacenter-Server-Core WindowsServer MicrosoftWindowsServer eastus 2016-Datacenter-Server-Core-smalldisk WindowsServer MicrosoftWindowsServer eastus 2016-Datacenter-smalldisk WindowsServer MicrosoftWindowsServer eastus 2016-Datacenter-with-Containers WindowsServer MicrosoftWindowsServer eastus 2016-Datacenter-with-RDSH WindowsServer MicrosoftWindowsServer eastus 2016-Nano-Server WindowsServer MicrosoftWindowsServer eastus
When you created a scale set at the start of the tutorial, a default VM image of Windows Server 2016 DataCenter was provided for the VM instances. You can specify a different VM image based on the output from Get-AzVMImageSku. The following example would create a scale set with the
-ImageName parameter to specify a VM image of MicrosoftWindowsServer:WindowsServer:2016-Datacenter-with-Containers:latest. As it takes a few minutes to create and configure all the scale set resources and VM instances, you don't have to deploy the following scale set:
New-AzVmss ` -ResourceGroupName "myResourceGroup2" ` -Location "EastUS" ` -VMScaleSetName "myScaleSet2" ` -VirtualNetworkName "myVnet2" ` -SubnetName "mySubnet2" ` -PublicIpAddressName "myPublicIPAddress2" ` -LoadBalancerName "myLoadBalancer2" ` -UpgradePolicyMode "Automatic" ` -ImageName "MicrosoftWindowsServer:WindowsServer:2016-Datacenter-with-Containers:latest" ` -Credential $cred
We recommend using the latest image version. Specify 'latest' to use the latest version of an image available at deploy time. Note, even if you use 'latest', the VM image will not automatically update after deploy time even if a new version becomes available.
Understand VM instance sizes
A VM instance size, or SKU, determines the amount of compute resources such as CPU, GPU, and memory that are made available to the VM instance. VM instances in a scale set need to be sized appropriately for the expected work load.
VM instance sizes
The following table categorizes common VM sizes into use cases.
|General purpose||Dsv3, Dv3, DSv2, Dv2, DS, D, Av2, A0-7||Balanced CPU-to-memory. Ideal for dev / test and small to medium applications and data solutions.|
|Compute optimized||Fs, F||High CPU-to-memory. Good for medium traffic applications, network appliances, and batch processes.|
|Memory optimized||Esv3, Ev3, M, GS, G, DSv2, DS, Dv2, D||High memory-to-core. Great for relational databases, medium to large caches, and in-memory analytics.|
|Storage optimized||Ls||High disk throughput and IO. Ideal for Big Data, SQL, and NoSQL databases.|
|GPU||NV, NC||Specialized VMs targeted for heavy graphic rendering and video editing.|
|High performance||H, A8-11||Our most powerful CPU VMs with optional high-throughput network interfaces (RDMA).|
Find available VM instance sizes
To see a list of VM instance sizes available in a particular region, use the Get-AzVMSize command.
Get-AzVMSize -Location "EastUS"
The output is similar to the following condensed example, which shows the resources assigned to each VM size:
Name NumberOfCores MemoryInMB MaxDataDiskCount OSDiskSizeInMB ResourceDiskSizeInMB ---- ------------- ---------- ---------------- -------------- -------------------- Standard_DS1_v2 1 3584 4 1047552 7168 Standard_DS2_v2 2 7168 8 1047552 14336 [...] Standard_A0 1 768 1 1047552 20480 Standard_A1 1 1792 2 1047552 71680 [...] Standard_F1 1 2048 4 1047552 16384 Standard_F2 2 4096 8 1047552 32768 [...] Standard_NV6 6 57344 24 1047552 389120 Standard_NV12 12 114688 48 1047552 696320
When you created a scale set at the start of the tutorial, a default VM SKU of Standard_DS1_v2 was provided for the VM instances. You can specify a different VM instance size based on the output from Get-AzVMSize. The following example would create a scale set with the
-VmSize parameter to specify a VM instance size of Standard_F1. As it takes a few minutes to create and configure all the scale set resources and VM instances, you don't have to deploy the following scale set:
New-AzVmss ` -ResourceGroupName "myResourceGroup3" ` -Location "EastUS" ` -VMScaleSetName "myScaleSet3" ` -VirtualNetworkName "myVnet3" ` -SubnetName "mySubnet3" ` -PublicIpAddressName "myPublicIPAddress3" ` -LoadBalancerName "myLoadBalancer3" ` -UpgradePolicyMode "Automatic" ` -VmSize "Standard_F1" ` -Credential $cred
Change the capacity of a scale set
When you created a scale set, you requested two VM instances. To increase or decrease the number of VM instances in the scale set, you can manually change the capacity. The scale set creates or removes the required number of VM instances, then configures the load balancer to distribute traffic.
First, create a scale set object with Get-AzVmss, then specify a new value for
sku.capacity. To apply the capacity change, use Update-AzVmss. The following example sets the number of VM instances in your scale set to 3:
# Get current scale set $vmss = Get-AzVmss -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet" # Set and update the capacity of your scale set $vmss.sku.capacity = 3 Update-AzVmss -ResourceGroupName "myResourceGroup" -Name "myScaleSet" -VirtualMachineScaleSet $vmss
If takes a few minutes to update the capacity of your scale set. To see the number of instances you now have in the scale set, use Get-AzVmss:
Get-AzVmss -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet"
The following example output shows that the capacity of the scale set is now 3:
Sku : Name : Standard_DS2 Tier : Standard Capacity : 3
Common management tasks
You can now create a scale set, list connection information, and connect to VM instances. You learned how you could use a different OS image for your VM instances, select a different VM size, or manually scale the number of instances. As part of day to day management, you may need to stop, start, or restart the VM instances in your scale set.
Stop and deallocate VM instances in a scale set
To stop one or more VMs in a scale set, use Stop-AzVmss. The
-InstanceId parameter allows you to specify one or more VMs to stop. If you do not specify an instance ID, all VMs in the scale set are stopped. The following example stops instance 1:
Stop-AzVmss -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet" -InstanceId "1"
By default, stopped VMs are deallocated and do not incur compute charges. If you wish the VM to remain in a provisioned state when stopped, add the
-StayProvisioned parameter to the preceding command. Stopped VMs that remain provisioned incur regular compute charges.
Start VM instances in a scale set
To start one or more VMs in a scale set, use Start-AzVmss. The
-InstanceId parameter allows you to specify one or more VMs to start. If you do not specify an instance ID, all VMs in the scale set are started. The following example starts instance 1:
Start-AzVmss -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet" -InstanceId "1"
Restart VM instances in a scale set
To restart one or more VMs in a scale set, use Retart-AzVmss. The
-InstanceId parameter allows you to specify one or more VMs to restart. If you do not specify an instance ID, all VMs in the scale set are restarted. The following example restarts instance 1:
Restart-AzVmss -ResourceGroupName "myResourceGroup" -VMScaleSetName "myScaleSet" -InstanceId "1"
Clean up resources
When you delete a resource group, all resources contained within, such as the VM instances, virtual network, and disks, are also deleted. The
-Force parameter confirms that you wish to delete the resources without an additional prompt to do so. The
-AsJob parameter returns control to the prompt without waiting for the operation to complete.
Remove-AzResourceGroup -Name "myResourceGroup" -Force -AsJob
In this tutorial, you learned how to perform some basic scale set creation and management tasks with Azure PowerShell:
- Create and connect to a virtual machine scale set
- Select and use VM images
- View and use specific VM sizes
- Manually scale a scale set
- Perform common scale set management tasks
Advance to the next tutorial to learn about scale set disks.