Instance level public ip address configuration in the cloud service.

An Instance-Level Public IP Address (PIP) unlike the Virtual IP Address (VIP) is not load balanced.  While the virtual ip is assigned to the cloud service and shared by all virtual machines and role instances in it, the public ip is associated only with a single instance’s NIC. The public ip is particularly useful in multi-instance deployments where each instance can be reachable independently from the Internet. The picture below illustrates the value of PIP and differentiates it from the VIP. The blog will help you understand how to configure the instance level public ip. 

 

 

For some background knowledge, please find the reference Instance-Level Public IP Address | Azure Blog and Updates | Microsoft Azure.

 

Classic cloud service:

1. How to configurate instance level public ip by role:

<?xml version="1.0" encoding="utf-8"?>

<ServiceConfiguration serviceName="TestVirtualnetwork" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="6" osVersion="*" schemaVersion="2015-04.2.6">

                <Role name="WebRole1">

                                <Instances count="1" />   

                                <ConfigurationSettings>     

                                                <Setting name="APPINSIGHTS_INSTRUMENTATIONKEY" value="xxx" />

                                </ConfigurationSettings>

                </Role>

                <Role name="WebRole2">

                                <Instances count="1" />

                                <ConfigurationSettings>

                                                <Setting name="APPINSIGHTS_INSTRUMENTATIONKEY" value="xxx" />

                                </ConfigurationSettings>

                </Role>

                <Role name="WebRole3">

                                <Instances count="1" />

                                <ConfigurationSettings>

                                <Setting name="APPINSIGHTS_INSTRUMENTATIONKEY" value="xxx" />

                                </ConfigurationSettings>

                </Role>

                <Role name="WebRole4">

                                <Instances count="1" />

                                <ConfigurationSettings>

                                <Setting name="APPINSIGHTS_INSTRUMENTATIONKEY" value="xxx" />

                                </ConfigurationSettings>

                </Role>

                <NetworkConfiguration>

                                <VirtualNetworkSite name="Group <resource group> <virtual network name>" />

                                <AddressAssignments>

                                                <InstanceAddress roleName="WebRole1">

                                                                <Subnets><Subnet name="subnet001" /></Subnets>

                                                                <PublicIPs><PublicIP name="PubIP" domainNameLabel="pip" /></PublicIPs>    // with domain

                                                </InstanceAddress>

                                                <InstanceAddress roleName="WebRole2">

                                                                <Subnets><Subnet name="subnet003" /></Subnets>

                                                                <PublicIPs><PublicIP name="PubIP"/></PublicIPs> // without domain

                                                </InstanceAddress>

                                </AddressAssignments>

                </NetworkConfiguration>

</ServiceConfiguration>

 

2. How to know current public ip of role:

 

• Powershell: We can use the Powershell command Get-AzureRole (Azure.Service) | Microsoft Learn based on the module Azure. With the above setting, we can see the difference from the Instance Details of each role instance.

Get-AzureRole -ServiceName <Cloud Service Name> -Slot Production -RoleName WebRole2 -InstanceDetails 

 

Get-AzureRole -ServiceName <Cloud Service Name> -Slot Production -RoleName WebRole1 -InstanceDetails

 

• The Azure Instance Metadata Service (IMDS) provides information about currently running virtual machine instances. You can use it to review your virtual machines’s NIC level setting. Azure Instance Metadata Service for Windows - Azure Virtual Machines | Microsoft Learn

•  

  Invoke-RestMethod -Headers @{"Metadata"="true"} -Method GET -NoProxy -Uri http://169.254.169.254/metadata/instance?api-version=2021-02-01 | ConvertTo-Json -Depth 64

 

Cloud Service Extended Support:

1. How to configurate instance level public ip by role:

<?xml version="1.0" encoding="utf-16"?>

<ServiceConfiguration xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" serviceName="Test_cloudservice" osFamily="6" osVersion="*" schemaVersion="2015-04.2.6" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration">

  <Role name="TestWebRole">

    <ConfigurationSettings>

      <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" />

    </ConfigurationSettings>

    <Instances count="2" />

  </Role>

  <Role name="TestWorkerRole">

    <ConfigurationSettings>

      <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" />

    </ConfigurationSettings>

    <Instances count="1" />

  </Role>

  <NetworkConfiguration>

    <VirtualNetworkSite name="test001VNet" />

    <AddressAssignments>

      <InstanceAddress roleName="TestWebRole">

        <Subnets>

          <Subnet name="default" />

        </Subnets>

        <PublicIPs>

          <PublicIP name="PubIP" domainNameLabel="pip" />

        </PublicIPs>

      </InstanceAddress>

      <InstanceAddress roleName="TestWorkerRole">

        <Subnets>

          <Subnet name="default" />

        </Subnets>

      </InstanceAddress>

      <ReservedIPs>

        <ReservedIP name="Group TESTCSES cses-prod" />

      </ReservedIPs>

    </AddressAssignments>

  </NetworkConfiguration>

</ServiceConfiguration>

 

2. Then, we can use the rest api PublicIPAddress In CloudService - List Cloud Service Public IP Addresses - REST API (Azure Virtual Networks) | Microsoft Learn to get the public ip of NIC.