Summary of the Pull Request

Using multiple Placement groups in Scalesets to scale upto 1000 VMs.

What is this about?
Earlier scaleset max size is restricted to 100 VMs because of using single placement group. Ref: https://docs.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-placement-groups#placement-groups
Using Multiple scalesets I can now scale to 1000s VM as per docs.

PR Checklist

• Applies to work item: #xxx
• CLA signed. If not, go over here and sign the CLI.
• Tests added/passed
• Requires documentation to be updated
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

Info on Pull Request

What does this include?
Setting single_placement_group to False while creating VMSS. Ref: https://docs.microsoft.com/en-us/python/api/azure-mgmt-compute/azure.mgmt.compute.v2020_06_01.models.virtualmachinescaleset?view=azure-python

Validation Steps Performed

How does someone test & validate?
Create a scaleset with of size more than 100 (provided you have minimum used quota of size specified left). Nodes are registered properly in the table.