Is it possible to assign public static IPs to individual VMs in Azure VMSS? - azure-vm-scale-set

Question

There is a document describing how to allocate a public IP per VM in VMSS: https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-networking#public-ipv4-per-virtual-machine
But it is not clear how to assign public static IP per VM. Is it possible?

Answer 1

Unfortunately, Azure does not provide control of the Public IP allocation method per instance in VMSS. You can see the all supported Properties of
VirtualMachineScaleSetPublicIPAddressConfigurationProperties object in the latest ARM API version.
However, after my validation, when you restart the instance or VMSS scale-in or scale-out, the public IP address of existing instances is not changed. The public IP address of instances will be updated unless you stop the instance of VMSS.
Update
Currently, you can manage it with IpPublicPrefix. Note that IpPublicPrefix requires a standard SKU load balancer and public IP address. Here is a working sample. You can check the public IP address of the instances in VMSS with the REST API.
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"vmSku": {
"type": "string",
"defaultValue": "Standard_A1_v2",
"metadata": {
"description": "Size of VMs in the VM Scale Set."
}
},
"windowsOSVersion": {
"type": "string",
"defaultValue": "2019-Datacenter",
"allowedValues": [
"2008-R2-SP1",
"2012-Datacenter",
"2012-R2-Datacenter",
"2016-Datacenter",
"2019-Datacenter"
],
"metadata": {
"description": "The Windows version for the VM. This will pick a fully patched image of this given Windows version. Allowed values: 2008-R2-SP1, 2012-Datacenter, 2012-R2-Datacenter & 2016-Datacenter, 2019-Datacenter."
}
},
"vmssName": {
"type": "string",
"minLength": 3,
"maxLength": 61,
"metadata": {
"description": "String used as a base for naming resources. Must be 3-61 characters in length and globally unique across Azure. A hash is prepended to this string for some resources, and resource-specific information is appended."
}
},
"instanceCount": {
"type": "int",
"defaultValue": 3,
"minValue": 1,
"maxValue": 100,
"metadata": {
"description": "Number of VM instances (100 or less)."
}
},
"singlePlacementGroup": {
"type": "bool",
"defaultValue": true,
"metadata": {
"description": "When true this limits the scale set to a single placement group, of max size 100 virtual machines. NOTE: If singlePlacementGroup is true, it may be modified to false. However, if singlePlacementGroup is false, it may not be modified to true."
}
},
"adminUsername": {
"type": "string",
"defaultValue": "vmssadmin",
"metadata": {
"description": "Admin username on all VMs."
}
},
"adminPassword": {
"type": "securestring",
"metadata": {
"description": "Admin password on all VMs."
}
},
"location": {
"type": "string",
"defaultValue": "[resourceGroup().location]",
"metadata": {
"description": "Location for all resources."
}
},
"platformFaultDomainCount": {
"type": "int",
"defaultValue": 1,
"metadata": {
"description": "Fault Domain count for each placement group."
}
},
"publicIPPrefixes_pubprefix_name": {
"defaultValue": "vmsspublicprefix",
"type": "string"
}
},
"variables": {
"namingInfix": "[toLower(substring(concat(parameters('vmssName'), uniqueString(resourceGroup().id)), 0, 9))]",
"longNamingInfix": "[toLower(parameters('vmssName'))]",
"addressPrefix": "10.0.0.0/16",
"subnetPrefix": "10.0.0.0/24",
"virtualNetworkName": "[concat(variables('namingInfix'), 'vnet')]",
"publicIPAddressName": "[concat(variables('namingInfix'), 'pip')]",
"subnetName": "[concat(variables('namingInfix'), 'subnet')]",
"loadBalancerName": "[concat(variables('namingInfix'), 'lb')]",
"publicIPAddressID": "[resourceId('Microsoft.Network/publicIPAddresses',variables('publicIPAddressName'))]",
"lbProbeID": "[resourceId('Microsoft.Network/loadBalancers/probes',variables('loadBalancerName'), 'tcpProbe')]",
"natPoolName": "[concat(variables('namingInfix'), 'natpool')]",
"bePoolName": "[concat(variables('namingInfix'), 'bepool')]",
"lbPoolID": "[resourceId('Microsoft.Network/loadBalancers/backendAddressPools',variables('loadBalancerName'),variables('bePoolName'))]",
"natStartPort": 50000,
"natEndPort": 50119,
"natBackendPort": 3389,
"nicName": "[concat(variables('namingInfix'), 'nic')]",
"ipConfigName": "[concat(variables('namingInfix'), 'ipconfig')]",
"frontEndIPConfigID": "[resourceId('Microsoft.Network/loadBalancers/frontendIPConfigurations',variables('loadBalancerName'),'loadBalancerFrontEnd')]",
"osType": {
"publisher": "MicrosoftWindowsServer",
"offer": "WindowsServer",
"sku": "[parameters('windowsOSVersion')]",
"version": "latest"
},
"imageReference": "[variables('osType')]"
},
"resources": [
{
"type": "Microsoft.Network/loadBalancers",
"apiVersion": "2020-06-01",
"name": "[variables('loadBalancerName')]",
"location": "[parameters('location')]",
"dependsOn": [
"[resourceId('Microsoft.Network/publicIPAddresses', variables('publicIPAddressName'))]"
],
"sku": {
"name": "Standard"
},
"properties": {
"frontendIPConfigurations": [
{
"name": "LoadBalancerFrontEnd",
"properties": {
"publicIPAddress": {
"id": "[variables('publicIPAddressID')]",
"name": "Standard"
}
}
}
],
"backendAddressPools": [
{
"name": "[variables('bePoolName')]"
}
],
"inboundNatPools": [
{
"name": "[variables('natPoolName')]",
"properties": {
"frontendIPConfiguration": {
"id": "[variables('frontEndIPConfigID')]"
},
"protocol": "Tcp",
"frontendPortRangeStart": "[variables('natStartPort')]",
"frontendPortRangeEnd": "[variables('natEndPort')]",
"backendPort": "[variables('natBackendPort')]"
}
}
],
"loadBalancingRules": [
{
"name": "LBRule",
"properties": {
"frontendIPConfiguration": {
"id": "[variables('frontEndIPConfigID')]"
},
"backendAddressPool": {
"id": "[variables('lbPoolID')]"
},
"protocol": "Tcp",
"frontendPort": 80,
"backendPort": 80,
"enableFloatingIP": false,
"idleTimeoutInMinutes": 5,
"probe": {
"id": "[variables('lbProbeID')]"
}
}
}
],
"probes": [
{
"name": "tcpProbe",
"properties": {
"protocol": "Tcp",
"port": 80,
"intervalInSeconds": 5,
"numberOfProbes": 2
}
}
]
}
},
{
"type": "Microsoft.Network/publicIPPrefixes",
"apiVersion": "2020-11-01",
"name": "[parameters('publicIPPrefixes_pubprefix_name')]",
"location": "[parameters('location')]",
"sku": {
"name": "Standard",
"tier": "Regional"
},
"properties": {
"prefixLength": 28,
"publicIPAddressVersion": "IPv4",
"ipTags": []
}
},
{
"type": "Microsoft.Compute/virtualMachineScaleSets",
"apiVersion": "2020-06-01",
"name": "[variables('namingInfix')]",
"location": "[parameters('location')]",
"sku": {
"name": "[parameters('vmSku')]",
"tier": "Standard",
"capacity": "[parameters('instanceCount')]"
},
"dependsOn": [
"[resourceId('Microsoft.Network/loadBalancers', variables('loadBalancerName'))]",
"[resourceId('Microsoft.Network/virtualNetworks', variables('virtualNetworkName'))]",
"[resourceId('Microsoft.Network/publicIPPrefixes',parameters('publicIPPrefixes_pubprefix_name'))]"
],
"properties": {
"overprovision": true,
"upgradePolicy": {
"mode": "Automatic"
},
"singlePlacementGroup": "[parameters('singlePlacementGroup')]",
"platformFaultDomainCount": "[parameters('platformFaultDomainCount')]",
"virtualMachineProfile": {
"storageProfile": {
"osDisk": {
"caching": "ReadWrite",
"createOption": "FromImage"
},
"imageReference": "[variables('imageReference')]"
},
"osProfile": {
"computerNamePrefix": "[variables('namingInfix')]",
"adminUsername": "[parameters('adminUsername')]",
"adminPassword": "[parameters('adminPassword')]"
},
"networkProfile": {
"networkInterfaceConfigurations": [
{
"name": "[variables('nicName')]",
"properties": {
"primary": true,
"ipConfigurations": [
{
"name": "[variables('ipConfigName')]",
"properties": {
"subnet": {
"id": "[resourceId('Microsoft.Network/virtualNetworks/subnets', variables('virtualNetworkName'), variables('subnetName'))]"
},
"loadBalancerBackendAddressPools": [
{
"id": "[variables('lbPoolID')]"
}
],
"loadBalancerInboundNatPools": [
{
"id": "[resourceId('Microsoft.Network/loadBalancers/inboundNatPools', variables('loadBalancerName'), variables('natPoolName'))]"
}
],
"publicipaddressconfiguration": {
"name": "pub1",
"properties": {
"idleTimeoutInMinutes": 15,
"publicIPAddressVersion": "IPv4",
"publicIPPrefix":{
"id": "[resourceId('Microsoft.Network/publicIPPrefixes',parameters('publicIPPrefixes_pubprefix_name'))]"
}
}
}
}
}
]
}
}
]
}
}
}
},
{
"type": "Microsoft.Network/publicIPAddresses",
"apiVersion": "2020-06-01",
"name": "[variables('publicIPAddressName')]",
"location": "[parameters('location')]",
"sku": {
"name": "Standard"
},
"properties": {
"publicIPAllocationMethod": "Static",
"dnsSettings": {
"domainNameLabel": "[variables('longNamingInfix')]"
}
}
},
{
"type": "Microsoft.Network/virtualNetworks",
"apiVersion": "2020-06-01",
"name": "[variables('virtualNetworkName')]",
"location": "[parameters('location')]",
"properties": {
"addressSpace": {
"addressPrefixes": [
"[variables('addressPrefix')]"
]
},
"subnets": [
{
"name": "[variables('subnetName')]",
"properties": {
"addressPrefix": "[variables('subnetPrefix')]"
}
}
]
}
},
{
"type": "Microsoft.Insights/autoscaleSettings",
"apiVersion": "2015-04-01",
"name": "autoscalehost",
"location": "[parameters('location')]",
"dependsOn": [
"[resourceId('Microsoft.Compute/virtualMachineScaleSets/', variables('namingInfix'))]"
],
"properties": {
"name": "autoscalehost",
"targetResourceUri": "[resourceId('Microsoft.Compute/virtualMachineScaleSets', variables('namingInfix'))]",
"enabled": true,
"profiles": [
{
"name": "Profile1",
"capacity": {
"minimum": "1",
"maximum": "10",
"default": "1"
},
"rules": [
{
"metricTrigger": {
"metricName": "Percentage CPU",
"metricResourceUri": "[resourceId('Microsoft.Compute/virtualMachineScaleSets', variables('namingInfix'))]",
"timeGrain": "PT1M",
"statistic": "Average",
"timeWindow": "PT5M",
"timeAggregation": "Average",
"operator": "GreaterThan",
"threshold": 50
},
"scaleAction": {
"direction": "Increase",
"type": "ChangeCount",
"value": "1",
"cooldown": "PT5M"
}
},
{
"metricTrigger": {
"metricName": "Percentage CPU",
"metricResourceUri": "[resourceId('Microsoft.Compute/virtualMachineScaleSets', variables('namingInfix'))]",
"timeGrain": "PT1M",
"statistic": "Average",
"timeWindow": "PT5M",
"timeAggregation": "Average",
"operator": "LessThan",
"threshold": 30
},
"scaleAction": {
"direction": "Decrease",
"type": "ChangeCount",
"value": "1",
"cooldown": "PT5M"
}
}
]
}
]
}
}
]
}