Tutorial: Add Azure Load Balancer to an existing Virtual Machine Scale Set using the Azure portal

The need may arise when an Azure Load Balancer isn't associated with a Virtual Machine Scale Set.

You may have an existing Virtual Machine Scale Set deployed with an Azure Load Balancer that requires updating.

The Azure portal can be used to add or update an Azure Load Balancer associated with a Virtual Machine Scale Set.

In this tutorial, you learn how to:

• Create a virtual network
• Create a NAT gateway for outbound connectivity
• Create a standard SKU Azure Load Balancer
• Create a virtual machine scale set without a load balancer
• Add a Azure Load Balancer to virtual machine scale set

Prerequisites

• An Azure account with an active subscription. Create an account for free

Create a virtual network

In this section, you'll create a virtual network for the scale set and the other resources used in the tutorial.

1. Sign in to the Azure portal.

2. In the search box at the top of the portal, enter Virtual network and select Virtual networks from the search results.

3. Select Create.

4. In the Basics tab of the Create virtual network, enter or select the following information:

   Setting	Value
   Project details
   Subscription	Select your subscription.
   Resource group	Select Create new. Enter myResourceGroup in Name. Select OK.
   Instance details
   Name	Enter myVNet.
   Region	Select (US) West US 2.

5. Select the IP addresses tab, or the Next: IP Addresses button at the bottom of the page.

6. In the IP addresses tab, select default under Subnet name.

7. In the Edit subnet pane, enter myBackendSubnet under Subnet name.

8. Select Save.

9. Select the Security tab, or the Next: Security button at the bottom of the page.

10. In the Security tab, in BastionHost select Enable.

11. Enter or select the following information:

    Setting	Value
    Bastion name	Enter myBastionHost.
    AzureBastionSubnet address space	Enter 10.1.1.0/26.
    Public IP address	Select Create new. Enter myBastionIP in Name.

12. Select the Review + create tab, or the blue Review + create button at the bottom of the page.

13. Select Create.

Create Virtual Machine Scale Set

In this section, you'll create a Virtual Machine Scale Set that will be attached to a load balancer created later.

1. In the search box at the top of the portal, enter Virtual machine scale, and select Virtual machine scale sets from the search results.

2. Select Create.

3. In the Basics tab of Create a virtual machine scale set, enter, or select the following information:

   Setting	Value
   Project details
   Subscription	Select your subscription.
   Resource group	Select myResourceGroup.
   Scale set details
   Virtual machine scale set name	Enter myVMScaleSet.
   Region	Select (US) West US 2.
   Availability zone	Leave the default of None.
   Orchestration
   Orchestration mode	Leave the default of Uniform: optimized for large-scale stateless workloads with identical instances.
   Security type	Leave the default of Standard
   Instance details
   Image	Select Windows Server 2022 Datacenter: Azure Edition - x64 Gen2.
   Azure Spot Instance	Leave the default of the box unchecked.
   Size	Select a size.
   Administrator account
   Username	Enter a username.
   Password	Enter a password.
   Confirm password	Confirm password.

4. Select the Networking tab.

5. Enter or select the following information in the Networking tab:

   Setting	Value
   Virtual network configuration
   Virtual network	Select myVNet.

6. Select the Review + create tab, or select the blue Review + create button at the bottom of the page.

7. Select Create.

Create NAT gateway

In this section, you'll create a NAT gateway for outbound connectivity of the virtual machines.

1. In the search box at the top of the portal, enter NAT gateway, and select NAT gateways in the search results.

2. Select + Create.

3. In the Basics tab of Create network address translation (NAT) gateway page, enter or select the following information:

   Setting	Value
   Project details
   Subscription	Select your subscription.
   Resource group	Select myResourceGroup.
   Instance details
   NAT gateway name	Enter myNATgateway.
   Region	Select (US) West US 2.
   Availability zone	Select None.
   Idle timeout (minutes)	Enter 15.

4. Select the Outbound IP tab, or select the Next: Outbound IP button at the bottom of the page.

5. Select Create a new public IP address next to Public IP addresses in the Outbound IP tab.

6. Enter myPublicIP-nat in Name.

7. Select OK.

8. Select the Subnet tab, or select the Next: Subnet button at the bottom of the page.

9. Select myVNet in the pull-down menu under Virtual network.

10. Select the check box next to myBackendSubnet.

11. Select the Review + create tab, or select the blue Review + create button at the bottom of the page.

12. Select Create.

Create load balancer

You'll create a load balancer in this section. The frontend IP, backend pool, load-balancing, and inbound NAT rules are configured as part of the creation.

1. In the search box at the top of the portal, enter Load balancer.

2. Select Load balancers in the search results.

3. Select + Create.

4. In the Basics tab of Create load balancer, enter, or select the following information:

   Setting	Value
   Project details
   Subscription	Select your subscription.
   Resource group	Select myResourceGroup.
   Instance details
   Name	Enter myLoadBalancer.
   Region	Select (US) West US 2.
   SKU	Leave the default of Standard.
   Type	Select Public.
   Tier	Leave the default of Regional.

5. Select Next: Frontend IP configuration at the bottom of the page.

6. In Frontend IP configuration, select + Add a frontend IP.

7. Enter myFrontend in Name.

8. Select IPv4 or IPv6 for the IP version.

   Note

   IPv6 isn't currently supported with Routing Preference or Cross-region load-balancing (Global Tier).

9. Select IP address for the IP type.

   Note

   For more information on IP prefixes, see Azure Public IP address prefix.

10. Select Create new in Public IP address.

11. In Add a public IP address, enter myPublicIP for Name.

12. Select Zone-redundant in Availability zone.

    Note

    In regions with Availability Zones, you have the option to select no-zone (default option), a specific zone, or zone-redundant. The choice will depend on your specific domain failure requirements. In regions without Availability Zones, this field won't appear.
    For more information on availability zones, see Availability zones overview.

13. Select Add.

14. Select Next: Backend pools at the bottom of the page.

15. In the Backend pools tab, select + Add a backend pool.

16. Enter or select the following information in Add backend pool.

    Setting	Value
    Name	Enter myBackendPool.
    Virtual network	Select myVNet (myResourceGroup).
    Backend Pool Configuration	Select NIC.
    IP version	Select IPv4.

17. Select Save.

18. Select the Review + create tab, or select the blue Review + create button at the bottom of the page.

19. Select Create.

Configure load balancer settings

In this section, you'll create a backend pool for myLoadBalancer.

You'll create a health probe to monitor HTTP and Port 80. The health probe will monitor the health of the virtual machines in the backend pool.

You'll create a load-balancing rule for Port 80 with outbound SNAT disabled. The NAT gateway you created earlier will handle the outbound connectivity of the virtual machines.

1. In the search box at the top of the portal, enter Load balancer.

2. Select Load balancers in the search results.

3. Select myLoadBalancer.

4. In myLoadBalancer, select Backend pools in Settings.

5. Select + Add in Backend pools.

6. In Add backend pool, enter or select the following information:

   Setting	Value
   Name	Enter myBackendPool.
   Virtual network	Select myVNet.
   Backend Pool Configuration	Leave the default of NIC.

7. Select Save.

8. Select Next: Inbound rules

9. In Create load balancer page, select + Add a load balancing rule.

10. Enter or select the following information in Add load-balancing rule:

    Setting	Value
    Name	Enter myHTTPRule.
    IP Version	Leave the default of IPv4.
    Frontend IP address	Select myFrontEnd.
    Backend pool	Select myBackendPool.
    Protocol	Select the default of TCP.
    Port	Enter 80.
    Backend port	Enter 80.
    Health probe	Select Create new. Enter myHTTPProbe for Name. Select HTTP for Protocol. Select Ok.
    Session persistence	Leave the default of None.
    Idle timeout (minutes)	Change the slider to 15.
    TCP reset	Select Enabled.
    Floating IP	Leave the default of Disabled.
    Outbound source network address translation (SNAT)	Leave the default of (Recommended) Use outbound rules to provide backend pool members access to the internet.

11. Select Add.

12. Select Review + Create and Create.

Add load balancer to scale set

In this section, you'll go to the scale set in the Azure portal and add a load balancer to the scale set.

1. In the search box at the top of the portal, enter Virtual machine scale.

2. In the search results, select Virtual machine scale sets.

3. Select myVMScaleSet.

4. In the Settings section of myVMScaleSet, select Networking.

5. Select the Load balancing tab in the Overview page of the Networking settings of myVMScaleSet.

   

6. Select the blue Add load balancing button.

7. In Add load balancing, enter or select the following information:

   Setting	Value
   Load balancing options	Select Azure load balancer.
   Select a load balancer	Select myLoadBalancer.
   Backend pool	Select Use existing.
   Select a backend pool	Select myBackendPool.

8. Select Save.

Clean up resources

If you're not going to continue to use this application, delete the load balancer and the supporting resources with the following steps:

1. In the search box at the top of the portal, enter Resource group.

2. Select Resource groups in the search results.

3. Select myResourceGroup.

4. In the overview page of myResourceGroup, select Delete resource group.

5. Enter myResourceGroup in TYPE THE RESOURCE GROUP NAME.

6. Select Delete.

Next steps

In this tutorial, you:

• Created a virtual network and Azure Bastion host.
• Created an Azure Standard Load Balancer.
• Created a virtual machine scale set.
• Added load balancer to Virtual Machine Scale Set.

Advance to the next article to learn how to create a cross-region Azure Load Balancer:

Create a cross-region load balancer