In this we will create scale set and set auto scaling rules for same.

vmss_create.sh

ImageName="presto-worker-image"
ScalesetName="presto-worker-scaleset"
ScalesetProfileName="presto-worker-scaleset-autoscale-profile"
AdminPassword="PasswordOfYourChoice"
ResourceGroupName="PrestoResourceGroup"
Subscription="Azure-Subscription-Name"
Location="eastus"
MIN_COUNT=2
MAX_COUNT=10
NsgName="presto-nsg"

# Create Scale Set
az vmss create \
  --subscription $Subscription \
  --resource-group $ResourceGroupName \
  --name $ScalesetName \
  --image $ImageName \
  --location $Location \
  --instance-count $MIN_COUNT \
  --upgrade-policy-mode "automatic" \
  --public-ip-per-vm \
  --nsg $NsgName \
  --admin-username azureuser \
  --admin-password $AdminPassword \
  --custom-data cloud-init.txt
  
# Create a scale set profile for autoscaler 
az monitor autoscale create \
  --subscription $Subscription \
  --resource-group $ResourceGroupName \
  --resource $ScalesetName \
  --resource-type "Microsoft.Compute/virtualMachineScaleSets" \
  --location $Location \
  --name $ScalesetProfileName \
  --min-count $MIN_COUNT \
  --max-count $MAX_COUNT \
  --count $MIN_COUNT
  
# Create a rule to autoscale out
az monitor autoscale rule create \
  --subscription $Subscription \
  --resource-group $ResourceGroupName \
  --autoscale-name $ScalesetProfileName \
  --condition "Percentage CPU > 70 avg 5m" \
  --cooldown 5 \
  --scale out 2
  
# Create a rule to autoscale in
az monitor autoscale rule create \
  --subscription $Subscription \
  --resource-group $ResourceGroupName \
  --autoscale-name $ScalesetProfileName \
  --condition "Percentage CPU < 30 avg 5m" \
  --cooldown 5 \
  --scale in 1