AVI Azure External Loadbalancer uses deprecated SKU

Products

VMware Avi Load Balancer

Issue/Introduction

Azure Cloud implementation of VMware Avi Load Balancer uses Azure Basic LB for various purposes such as Cluster VIP configuration, vsVIP placement and Public IPs. Azure Basic ALB will retired on 30th September 2025, with support to deploy new ALBs of Basic SKU going away on 31 March 2025. As a result, some customers require a migration path from Basic to Standard SKU ALB. This doc presents the steps to migrate to Standard ALB for Avi Resources.

Announcement by Microsoft
https://azure.microsoft.com/en-us/updates?id=azure-basic-load-balancer-will-be-retired-on-30-september-2025-upgrade-to-standard-load-balancer
Azure Upgrade Reference
https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-basic-upgrade-guidance

Environment

Azure

Cause

How to migrate the Virtual Service from Basic SKU ALB to Standard SKU ALB

Resolution

In Azure Cloud, we cannot directly upgrade the SKU.

To change the SKU type, migrate VSs from existing SEG (with basic SKU - standard_alb as false) to a new SEG with standard_alb as true. It will create new lbs of standard sku, with older config.

There are different workflows for Virtual Service migration depending on type of vsVIPs used:

Private IPs only in VS VIP
Private and Public IPs in VS VIP

Below are workflows for these use-cases:

1. Private IPs in your VsVip

Disable all Virtual services and delete all the SEs.

Create a new SEG (clone) with knob use_standard_alb set to true (By default Basic SKU Load Balancer is used)

// By default "use_standard_alb" knob set to FALSE for 22.x and 30.x releases.

[admin:]: > show serviceenginegroup <New-ServiceEngineGroup-Name> | grep use_standard_alb
| use_standard_alb                        | False                                                   |

// How to enable "use_standard_alb" setting in Service Engine Group via CLI

[admin:]: > configure serviceenginegroup <New-ServiceEngineGroup-Name>
[admin:]: serviceenginegroup> use_standard_alb
[admin:]: serviceenginegroup> save

[admin:]: > show serviceenginegroup Default-Group | grep use_standard_alb
| use_standard_alb                        | True                                                    |

Migrate the VS to the new SEG (change the VS SEG)

https://techdocs.broadcom.com/us/en/vmware-security-load-balancing/avi-load-balancer/avi-load-balancer/22-1/vmware-avi-load-balancer-configuration-guide/load-balancing-overview/virtual-services/migrating-virtual-services.html
Re-enable the VS, wait for the SEs to come up in the new SEG, and network programming to finish.
You may delete the old SEG once the migration is complete.

2. Private and Public IPs in your VsVip:

Create a new SEG (clone) with knob use_standard_alb set to true (By default Basic SKU Load Balancer is used.)
Save the VS Configurations and Delete the VSs. With current implementation, Public IPs can’t be disassociated and attached back for changed config hence deletion is needed for Virtual Services.
Recreate new virtual services with saved configuration (SE Group pointing to newly created SE Group in step#1) and with a new VsVip.
VsVip can have both public and private IPs as required.
Wait for the SEs to come up in the new SEG, and network programming to finish.
Once network programming finishes, you may also have to update your DNS entries to reflect the new Private/Public IPs.
You may delete the old SEG once the migration is complete.
Note: It require to associate a NAT gateway with a Public IP address or a prefix to the subnet of the Avi Controller is required for the outbound access.

Please note that Starting with Avi Controller version 31.1.x, a new cluster VIP will be created with the standard LB as the default mode and with no option to revert to the Basic LB.

Impact on new Cluster VIPs post migration to 31.1.1 –
Creating without a NAT gateway set up for the controller subnets will result in all cloud programming ceasing to function including Cluster VIP programming itself due to lack of outbound reachability from all the controller nodes.

Impact on previously configured (pre-31.1.1) Cluster VIPs post migration to 31.1.1

Cluster VIPs with Basic LB will continue to work till Azure supports it (30th September 2025). Post migration, Avi Load Balancer will continue to use Azure Basic LB for Cluster VIP. For the Azure Standard LB based VIP to take effect, you need to unset the Cluster VIP and set it again.

Additional Information

Azure LB Upgrade Reference - https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-basic-upgrade-guidance