Large VMSS with singlePlacementGroup=false behind Public Load Balancer SKU=Standard has no outbound connection

[evertonmc]

When deploying a (planned to be) large VMSS inside a vnet, this doc recommends to set singlePlacementGroup=false in order to support >100 VMs.
This kind of VMSS (100+) can only get load balanced from a LB-Standard (preview).
Nevertheless, when using both settings, the instances are not able to get outbound traffic no matter what NSG rules I try.

Deploying the same setup with Basic LB or singlePlacementGroup recovers the outbound traffic.

[gbowerman]

@christiankuhtz @gatneil can you take a look at this?

[gatneil]

@evertonmc did you add PIP per VM or load balancing rules from the public LB? With Standard LB, you must have at least one of these to get outbound connectivity. Sample template here: https://github.com/Azure/vm-scale-sets/blob/master/preview/zones/multizone.json. This behavior is documented here: https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-standard-overview#outboundconnections

Let me know if you have further questions! :)

[evertonmc]

Hi. I have a PIP (Standard) bound to the LB (also Standard). You can reproduce this issue by deploying your template with singlePlacementGroup = false

[gatneil]

Can you share your template? A PIP on the LB is not enough. You must either have a PIP per VM or load balancing rules from the public LB to the scale set. This is new behavior in Standard Load Balancer

[evertonmc]

yes I can, on monday. I am currently using the Standard LB successfully. The problem is, that I can't deactivate singlePlacementGroup in order to scale to > 100 VMs

[evertonmc]

https://gist.github.com/evertonmc/5550de54b03940745aa683623155c289
This deployment is working as long as I don't set singlePlacementGroup=false

[evertonmc]

Anything new here?