Auto scaling not working with VMSS

[hitesh1907nayyar]

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I have enabled vmss as per the link: https://docs.microsoft.com/en-us/azure/aks/cluster-autoscaler#enable-the-cluster-autoscaler-on-an-existing-aks-cluster
and created new cluster using terraform but still i am getting the error:
az aks update \

--resource-group cluster2
--name k8stestvmms
--enable-cluster-autoscaler
--min-count 1
--max-count 3
Operation failed with status: 'Bad Request'. Details: AgentPool 'agentpool' has set auto scaling as enabled but is not on Virtual Machine Scale Sets, this is not allowed.

$ az feature list -o table --query "[?contains(name, 'Microsoft.ContainerService/VMSSPreview')].{Name:name,State:properties.state}"

Name State

---

Microsoft.ContainerService/VMSSPreview Registered

---

Document Details

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• ID: 077f1bb5-2ba9-490c-2c6e-0de292266539
• Version Independent ID: 0fd87b4f-88a4-c2eb-3ebc-f2b113ac203c
• Content: Use the cluster autoscaler in Azure Kubernetes Service (AKS)
• Content Source: articles/aks/cluster-autoscaler.md
• Service: container-service
• GitHub Login: @iainfoulds
• Microsoft Alias: iainfou

[KetanChawda-MSFT]

@hitesh1907nayyar Thank you for your feedback! We will review and provide an update as appropriate.

[Karishma-Tiwari-MSFT]

@hitesh1907nayyar This issue is same as #24942
As noted in the opening section:

AKS clusters that support the cluster autoscaler must use virtual machine scale sets and run Kubernetes version 1.12.4 or later. This scale set support is in preview. To opt in and create clusters that use scale sets, install the aks-preview Azure CLI extension

Creating an AKS cluster through the portal doesn't meet these requirements. You must install the aks-preview extension and create the cluster through the CLI. You can do this from the Cloud Shell in the portal if you prefer.

As also noted in the article:

The cluster autoscaler is a Kubernetes component. Although the AKS cluster uses a virtual machine scale set for the nodes, don't manually enable or edit settings for scale set autoscale in the Azure portal or using the Azure CLI. Let the Kubernetes cluster autoscaler manage the required scale settings.

What you're currently seeing on a regular AKS cluster without scale set support is manually scaling the number of nodes. When you create a cluster that uses scale sets, you don't use any of the scale options in the portal. Let the cluster autoscaler manage settings from within the cluster itself.

We will now close this issue. If there are further questions regarding this matter, please tag me in a comment. I will reopen it and we will gladly continue the discussion.