Azure Resource Manager - Multiple VM NAT Rules - azure-resource-manager

Question

I am trying to create an ARM template that will provision multiple webservers with directly accessible ports. For instance I want a VM to have either port 9001 or 9002 open based on what the index of the VM is.
I am struggling to get the frontendPort parameter to accept a function. Here is the documentation that I have used.
Here is what the relevant portion of my template looks like:
"inboundNatRules": [
{
"copy": {
"name": "natCopy",
"count": "[parameters('numberOfVms')]"
},
"name": "[concat('directHttps-', copyIndex())]",
"properties": {
"frontendIPConfiguration": {
"id": "[concat(variables('lbID'),'/frontendIPConfigurations/LoadBalancerFrontEnd')]"
},
"frontendPort": "[add(9001, copyIndex())]",
"backendPort": 9001,
"enableFloatingIP": false,
"idleTimeoutInMinutes": 4,
"protocol": "Tcp",
"backendIPConfiguration": {
"id": "[resourceId('Microsoft.Network/networkInterfaces', concat(variables('vmNicName'), copyIndex()), 'ipconfig')]"
}
}
}
]
I was hoping that the this particular port would result in either "9001", or "9002".
"frontendPort": "[add(9001, copyIndex())]"
Instead, I see an error in Visual Studio's Intellisense, and when I try to deploy the solution.
Create template deployment 'deploymenttemplate-0107-1555'.
New-AzureRmResourceGroupDeployment : Resource Microsoft.Network/loadBalancers 'webserverLb'
failed with message 'Unable to process template language expressions for resource
'/subscriptions/some random guid/resourceGroups/webservers/providers/Microsoft.Network/loadBalancers/webserverLb'
at line '102' and column '10'. 'The template function 'copyIndex' is not expected at this location.
The function can only be used in a resource with copy specified.
Long story short, I'm simply trying to have the same number of NAT rules as I have VM's in the template, and dynamically assign the external port number.
Please let me know if I can provide any more information. Thank you.

Answer 1

Try:
[Concat(900,CopyIndex(1))]
which will offset the index (0 based) and give you the number you want.

Answer 2

This is the syntax that works for copying the NAT rules (I am adding an RDP rule on the standard back-end port):
"copy": [
{
"name": "inboundNatRules",
"count": "[parameters('numberOfWebInstances')]",
"input": {
"name": "[concat(parameters('lbNatRulePrefix'), copyindex('inboundNatRules'))]",
"properties": {
"frontendIPConfiguration": {
"id": "[variables('lbFrontEndIpId')]"
},
"frontendPort": "[add(50001, copyIndex('inboundNatRules'))]",
"backendPort": 3389,
"enableFloatingIP": false,
"idleTimeoutInMinutes": 4,
"protocol": "tcp"
}
}
}
],
And then to apply the rules to the NIC, you actually need to add some code on the NIC itself. The following is for both LB rules and NAT rules:
"loadBalancerBackendAddressPools": [
{
"id": "[concat(variables('lbID'), '/backendAddressPools/', parameters('lbPoolName'))]"
}
],
"loadBalancerInboundNatRules": [
{
"id": "[concat(variables('lbID'),'/inboundNatRules/' , parameters('lbNatRulePrefix'), copyindex())]"
}
]

Answer 3

#Your script is wrong it should you are writing copyindex() but you need to pass the name of rule it should work.
"inboundNatRules": [
{
"copy": {
"name": "natCopy",
"count": "[parameters('numberOfVms')]"
},
"name": "[concat('directHttps-', copyIndex(natCopy,1))]",
"properties": {
"frontendIPConfiguration": {
"id": "[concat(variables('lbID'),'/frontendIPConfigurations/LoadBalancerFrontEnd')]"
},
"frontendPort": "[add(9001, copyIndex(natCopy,1))]",
"backendPort": 9001,
"enableFloatingIP": false,
"idleTimeoutInMinutes": 4,
"protocol": "Tcp",
"backendIPConfiguration": {
"id": "[resourceId('Microsoft.Network/networkInterfaces', concat(variables('vmNicName'), copyIndex(natCopy,1)), 'ipconfig')]"
}
}
}

Answer 4

$LoadBalancer = Get-AzureRmLoadBalancer -ResourceGroupName $ResourceGroupName -Name $LoadBalancerName
$publicIP1 = Get-AzureRmPublicIpAddress -name $pipName -resourcegroupname $ResourceGroupName
$frontendIP1 = Get-AzureRmLoadBalancerFrontendIpConfig -LoadBalancer $LoadBalancer -Name $FrontendIpConfigName
$LoadBalancer | Add-AzureRmLoadBalancerInboundNatRuleConfig -Name "nat_rule_tcp_IP1_49157" -FrontendIpConfiguration $frontendIP1 -IdleTimeoutInMinutes 4 -Protocol TCP -FrontendPort 49157 -BackendPort 49157 | Set-AzureRmLoadBalancer