Migrate Loadbalancer Basic SKU to Standard SKU gives error

Question

Migrate Loadbalancer Basic SKU to Standard SKU gives error

Basam Ahmad 0

Start-AzBasicLoadBalancerUpgrade -ResourceGroupName CAC-RSG-FIO-UAT -BasicLoadBalancerName elb-AS-WEB-UAT

Write-Error: 2025-08-08T23:58:40-04 [Error]:[Test-SupportedMigrationScenario] VMs

('/subscriptions/72a14156-35ab-46f2-8889-3c66ab84f260/resourceGroups/CAC-RSG-FIO-UAT/providers/Microsoft.Compute/virtual

Machines/UAT-VM-IIS-02') belong(s) to an Availability Set but is not associated with the LB. There are other members of

the same Availability Set which are part of the load balancer backend pools, NAT pools, or associated with NAT Rules.

This is not supported for migration. To work around this, create a new backend pool on the basic LB which is not

associated with a load balancing rule and add the extra VMs to it temporarily, then retry migration.

G Sree Vidya 4,005 Reputation points Microsoft External Staff Moderator

2025-08-11T01:24:57.3733333+00:00

Hello Basam Ahmad

I wanted to follow up and check if you had the opportunity to review the information provided by Obinna Ejidike in our previous post.

Kindly let us know if the above helps or you need further assistance on this issue.
Praveen Bandaru 6,850 Reputation points Microsoft External Staff Moderator

2025-08-12T02:25:04.2266667+00:00

Hello Basam Ahmad

I wanted to follow up to see if you had a chance to review Obinna Ejidike's response to your question. Let us know if it was helpful, and if you have any other questions, please feel free to ask.

Hope the above answer helps! Please let us know do you have any further queries.

Please do not forget to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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G Sree Vidya 4,005 Reputation points Microsoft External Staff Moderator

2025-08-11T01:24:57.3733333+00:00

Hello Basam Ahmad

I wanted to follow up and check if you had the opportunity to review the information provided by Obinna Ejidike in our previous post.

Kindly let us know if the above helps or you need further assistance on this issue.
Praveen Bandaru 6,850 Reputation points Microsoft External Staff Moderator

2025-08-12T02:25:04.2266667+00:00

Hello Basam Ahmad

I wanted to follow up to see if you had a chance to review Obinna Ejidike's response to your question. Let us know if it was helpful, and if you have any other questions, please feel free to ask.

Hope the above answer helps! Please let us know do you have any further queries.

Please do not forget to “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

Answer 1

Hi Basam Ahmad

Thanks for using the Q&A platform.

You're encountering a known limitation during migration; if even one VM in an Availability Set isn’t part of the Basic Load Balancer's backend pool, the in-place upgrade will fail. The Azure upgrade guidance explicitly lists this as an unsupported scenario.
User's image

Find https://github.com/MicrosoftDocs/azure-docs/blob/main/articles/load-balancer/upgrade-basic-standard-with-powershell.md?

Recommendation would be to temporarily add all VMs in the Availability Set into a backend pool, even if some aren't serving traffic through that LB. Kindly check our previous feedback on the same issue and provided suggestions: https://learn.microsoft.com/en-us/answers/questions/4375236/upgrading-load-balancer-from-basic-to-standard-sku?

If the response was helpful, please feel free to mark it as “Accepted Answer” and consider giving it an upvote. This also benefits others in the community.
Regards,

Obinna.

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Migrate Loadbalancer Basic SKU to Standard SKU gives error

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