Merge pull request #225074 from rpsqrd/arc-server-vdi

Adding VDI and client OS details to Arc server docs

Author: denrea

articles/azure-arc/servers/prerequisites.md

@@ -1,13 +1,13 @@
 ---
 title: Connected Machine agent prerequisites
 description: Learn about the prerequisites for installing the Connected Machine agent for Azure Arc-enabled servers.
-ms.date: 11/18/2022
+ms.date: 01/25/2023
 ms.topic: conceptual 
 ---
 
 # Connected Machine agent prerequisites
 
-This topic describes the basic requirements for installing the Connected Machine agent to onboard a physical server or virtual machine to Azure Arc-enabled servers. Some [onboarding methods](deployment-options.md) may have additional requirements.
+This topic describes the basic requirements for installing the Connected Machine agent to onboard a physical server or virtual machine to Azure Arc-enabled servers. Some [onboarding methods](deployment-options.md) may have more requirements.
 
 ## Supported environments
 
@@ -17,18 +17,27 @@ Azure Arc-enabled servers support the installation of the Connected Machine agen
 * Azure Stack HCI
 * Other cloud environments
 
-Azure Arc-enabled servers do not support installing the agent on virtual machines running in Azure, or on virtual machines running on Azure Stack Hub or Azure Stack Edge, as they are already modeled as Azure VMs and able to be managed directly in Azure.
+You shouldn't install Azure Arc on virtual machines hosted in Azure, Azure Stack Hub, or Azure Stack Edge, as they already have similar capabilities. You can, however, [use an Azure VM to simulate an on-premises environment](plan-evaluate-on-azure-virtual-machine.md) for testing purposes, only.
+
+Take extra care when using Azure Arc on systems that are:
+
+* Cloned
+* Restored from backup as a second instance of the server
+* Used to create a "golden image" from which other virtual machines are created
+
+If two agents use the same configuration, you will encounter inconsistent behaviors when both agents try to act as one Azure resource. The best practice for these situations is to use an automation tool or script to onboard the server to Azure Arc after it has been cloned, restored from backup, or created from a golden image.
 
 > [!NOTE]
-> For additional information on using Arc-enabled servers in VMware environments, see the [VMware FAQ](vmware-faq.md).
+> For additional information on using Azure Arc-enabled servers in VMware environments, see the [VMware FAQ](vmware-faq.md).
 
 ## Supported operating systems
 
-The following versions of the Windows and Linux operating system are officially supported for the Azure Connected Machine agent. Only x86-64 (64-bit) architectures are supported. x86 (32-bit) and ARM-based architectures, including x86-64 emulation on arm64, are not supported operating environments.
+Azure Arc supports the following Windows and Linux operating systems. Only x86-64 (64-bit) architectures are supported. Azure Arc does not run on x86 (32-bit) or ARM-based architectures.
 
 * Windows Server 2008 R2 SP1, 2012 R2, 2016, 2019, and 2022
   * Both Desktop and Server Core experiences are supported
-  * Azure Editions are supported when running as a virtual machine on Azure Stack HCI
+  * Azure Editions are supported on Azure Stack HCI
+* Windows 10, 11 (see [client operating system guidance](#client-operating-system-guidance))
 * Windows IoT Enterprise
 * Azure Stack HCI
 * Ubuntu 16.04, 18.04, 20.04, and 22.04 LTS
@@ -40,24 +49,28 @@ The following versions of the Windows and Linux operating system are officially
 * Amazon Linux 2
 * Oracle Linux 7 and 8
 
-> [!NOTE]
-> On Linux, Azure Arc-enabled servers install several daemon processes. We only support using systemd to manage these processes. In some environments, systemd may not be installed or available, in which case Arc-enabled servers are not supported, even if the distribution is otherwise supported. These environments include **Windows Subsystem for Linux** (WSL) and most container-based systems, such as Kubernetes or Docker. The Azure Connected Machine agent can be installed on the node that runs the containers but not inside the containers themselves.
+### Client operating system guidance
 
-> [!WARNING]
-> If the Linux hostname or Windows computer name uses a reserved word or trademark, attempting to register the connected machine with Azure will fail. For a list of reserved words, see [Resolve reserved resource name errors](../../azure-resource-manager/templates/error-reserved-resource-name.md).
+The Azure Arc service and Azure Connected Machine Agent are supported on Windows 10 and 11 client operating systems only when using those computers in a server-like environment. That is, the computer should always be:
 
-> [!NOTE]
-> While Azure Arc-enabled servers support Amazon Linux, the following features are not supported by this distribution:
->
-> * The Dependency agent used by Azure Monitor VM insights
-> * Azure Automation Update Management
+* Connected to the internet
+* Connected to a power source
+* Powered on
+
+For example, a computer running Windows 11 that's responsible for digital signage, point-of-sale solutions, and general back office management tasks is a good candidate for Azure Arc. End-user productivity machines, such as a laptop, which may go offline for long periods of time, shouldn't use Azure Arc and instead should consider [Microsoft Intune](/mem/intune) or [Microsoft Endpoint Configuration Manager](/mem/configmgr).
+
+### Short-lived servers and virtual desktop infrastructure
+
+Microsoft doesn't recommend running Azure Arc on short-lived (ephemeral) servers or virtual desktop infrastructure (VDI) VMs. Azure Arc is designed for long-term management of servers and isn't optimized for scenarios where you are regularly creating and deleting servers. For example, Azure Arc doesn't know if the agent is offline due to planned system maintenance or if the VM was deleted, so it won't automatically clean up server resources that stopped sending heartbeats. As a result, you could encounter a conflict if you re-create the VM with the same name and there's an existing Azure Arc resource with the same name.
+
+[Azure Virtual Desktop on Azure Stack HCI](../../virtual-desktop/azure-stack-hci-overview.md) doesn't use short-lived VMs and supports running Azure Arc in the desktop VMs.
 
 ## Software requirements
 
 Windows operating systems:
 
-* NET Framework 4.6 or later is required. [Download the .NET Framework](/dotnet/framework/install/guide-for-developers).
-* Windows PowerShell 4.0 or later is required. No action is required for Windows Server 2012 R2 and above. For Windows Server 2008 R2 SP1, [Download Windows Management Framework 5.1.](https://www.microsoft.com/download/details.aspx?id=54616).
+* NET Framework 4.6 or later. [Download the .NET Framework](/dotnet/framework/install/guide-for-developers).
+* Windows PowerShell 4.0 or later (already included with Windows Server 2012 R2 and later). For Windows Server 2008 R2 SP1, [Download Windows Management Framework 5.1.](https://www.microsoft.com/download/details.aspx?id=54616).
 
 Linux operating systems:
 
@@ -68,17 +81,17 @@ Linux operating systems:
 
 ## Required permissions
 
-The following Azure built-in roles are required for different aspects of managing connected machines:
+You'll need the following Azure built-in roles for different aspects of managing connected machines:
 
-* To onboard machines, you must have the [Azure Connected Machine Onboarding](../../role-based-access-control/built-in-roles.md#azure-connected-machine-onboarding) or [Contributor](../../role-based-access-control/built-in-roles.md#contributor) role for the resource group in which the machines will be managed.
+* To onboard machines, you must have the [Azure Connected Machine Onboarding](../../role-based-access-control/built-in-roles.md#azure-connected-machine-onboarding) or [Contributor](../../role-based-access-control/built-in-roles.md#contributor) role for the resource group where you're managing the servers.
 * To read, modify, and delete a machine, you must have the [Azure Connected Machine Resource Administrator](../../role-based-access-control/built-in-roles.md#azure-connected-machine-resource-administrator) role for the resource group.
-* To select a resource group from the drop-down list when using the **Generate script** method, as well as the permissions needed to onboard machines, listed above, you must additionally have the [Reader](../../role-based-access-control/built-in-roles.md#reader) role for that resource group (or another role which includes **Reader** access).
+* To select a resource group from the drop-down list when using the **Generate script** method, you'll also need the [Reader](../../role-based-access-control/built-in-roles.md#reader) role for that resource group (or another role that includes **Reader** access).
 
 ## Azure subscription and service limits
 
 There are no limits to the number of Azure Arc-enabled servers you can register in any single resource group, subscription or tenant.
 
-Each Azure Arc-enabled server is associated with an Azure Active Directory object and will count against your directory quota. See [Azure AD service limits and restrictions](../../active-directory/enterprise-users/directory-service-limits-restrictions.md) for information about the maximum number of objects you can have in an Azure AD directory.
+Each Azure Arc-enabled server is associated with an Azure Active Directory object and counts against your directory quota. See [Azure AD service limits and restrictions](../../active-directory/enterprise-users/directory-service-limits-restrictions.md) for information about the maximum number of objects you can have in an Azure AD directory.
 
 ## Azure resource providers
 
@@ -89,7 +102,7 @@ To use Azure Arc-enabled servers, the following [Azure resource providers](../..
 * **Microsoft.HybridConnectivity**
 * **Microsoft.AzureArcData** (if you plan to Arc-enable SQL Servers)
 
-If these resource providers are not already registered, you can register them using the following commands:
+You can register the resource providers using the following commands:
 
 Azure PowerShell:
 
@@ -99,6 +112,7 @@ Set-AzContext -SubscriptionId [subscription you want to onboard]
 Register-AzResourceProvider -ProviderNamespace Microsoft.HybridCompute
 Register-AzResourceProvider -ProviderNamespace Microsoft.GuestConfiguration
 Register-AzResourceProvider -ProviderNamespace Microsoft.HybridConnectivity
+Register-AzResourceProvider -ProviderNamespace Microsoft.AzureArcData
 ```
 
 Azure CLI:
@@ -108,6 +122,7 @@ az account set --subscription "{Your Subscription Name}"
 az provider register --namespace 'Microsoft.HybridCompute'
 az provider register --namespace 'Microsoft.GuestConfiguration'
 az provider register --namespace 'Microsoft.HybridConnectivity'
+az provider register --namespace 'Microsoft.AzureArcData'
 ```
 
 You can also register the resource providers in the [Azure portal](../../azure-resource-manager/management/resource-providers-and-types.md#azure-portal).