Basic Load Balancer with scale set "Virtual Machine Scale Set cannot use a basic SKU load balancer when singlePlacementGroup property is false (lar)."

Question

I am creating BasicLoadBalancer on Azure with scaleset. While adding the backend pool scaleset instance getting an below error

Virtual Machine Scale Set cannot use a basic SKU load balancer when singlePlacementGroup property is false (large scale enabled).

Answer 1

I am able to add the Basic Load Balancer with Virtual Machine Scale after below steps

1. Deleted existing scale set as we have max of 100 only vm can scale.
2. Re-crated the scale set as Virtual Machine Scale Set -> update ResourceGrup/Name/Region/ -> Disk -> Networking -> Scaling -> Management -> Health ->Advanced (Here uncheck "Allocation policy>Enable scaling beyond 100 instances) -> Tag -> Review and Create.

After re-creating by unchecking Enable Scaling beyound 100 instance, able to add back end pool with Basic Load Balancer. thank you

Answer 2

Documentation: Working with large virtual machine scale sets

With single placement group a scale set can have up to 100 VMs.

With multiple placement groups a scale set can have up to 1000 VMs. It requires Standard Load Balancer though, Basic won't work.

You can specify singlePlacementGroup when deploying through all of Portal, CLI or ARM. Unless you want >100 instances, in which case the only option is multiple placement groups.