I am trying to enable cluster Autoscaling on existing AKS Cluster using Azure CLI. Please find the below command which I have used.

az aks update --resource-group prod-rg --name prod-aks-cluster  --enable-cluster-autoscaler --min-count 3 --max-count 4

I am getting the following exception while executing the above command.

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. Please see https://aka.ms/aks-vmss-enablement for more details.

From the above exception, I have understood that the Virtual Machine Scale Sets is not enabled in my Cluster. Is there any way I can enable the Virtual Machine Scale Sets in existing Cluster or Enable Cluster Autoscalar in existing Cluster without Virtual Machine Scale Sets. Any help will be appreciated.

AKS Cluster version : 1.13.12 Azure CLI Version : 2.0.77

I have referred to the link: https://docs.microsoft.com/en-us/azure/aks/cluster-autoscaler