Manage configurations for Azure Arc enabled servers

This reference architecture illustrates how Azure Arc enables you to manage, govern, and secure servers across on-premises, multiple cloud, and edge scenarios.

An Azure Arc hybrid server topology diagram with Arc enabled servers connected to Azure.

Download a Visio file of this architecture.

Typical uses for this architecture include:

  • Organize, govern, and inventory large groups of virtual machines (VMs) and servers across multiple environments.
  • Enforce organization standards and assess compliance at scale for all your resources anywhere with Azure Policy.
  • Easily deploy extensions to Azure VMs and Arc enabled servers.
  • Configure and enforce Azure Policy for VMs and servers hosted across multiple environments.

Architecture

The architecture consists of the following components:

  • Azure Arc. Azure Arc enables you to connect Azure to your Windows and Linux machines hosted outside of Azure on your corporate network. When a server is connected to Azure, it becomes an Arc enabled server and is treated as a resource in Azure. Each Arc enabled server has a Resource ID, a managed system identity, and is managed as part of a resource group inside a subscription. Arc enabled servers benefit from standard Azure constructs such as inventory, policy, tags, and Azure Lighthouse.
  • Azure VMs. Azure VMs include Windows or Linux VMs hosted in Azure.
  • Azure Policy Guest Configuration. Azure Policy Guest Configuration can audit operating systems and machine configuration both for machines running in Azure and Arc enabled servers running on-premises or in other clouds.
  • Azure Monitor. Azure Monitor enables you to track performance and events for systems running in Azure, on-premises, or in other clouds.

Recommendations

The following recommendations apply for most scenarios. Follow these recommendations unless you have a specific requirement that overrides them.

Connecting machines to Azure Arc

You can connect any other physical or virtual machine running Windows or Linux to Azure Arc. To use Azure Arc to connect the machine to Azure, you need to install the Azure Connected Machine agent on each machine that you plan to connect using Azure Arc.

Once configured, the Connected Machine agent sends a regular heartbeat message every five minutes to Azure. When the heartbeat is not received, Azure assigns the machine Offline status, which is reflected in the portal within 15 to 30 minutes. Upon receiving a subsequent heartbeat message from the Connected Machine agent, its status will automatically change to Connected.

Manual installation

You can enable Azure Arc for servers for one or a few Windows or Linux machines in your environment by using the Windows Admin Center tool set or by performing a set of steps manually. You can download the Windows agent Windows Installer package from the Microsoft Download Center or the Linux agent from Microsoft's package repository.

For more information, refer to Overview of Azure Arc for servers agent.

Script-based installation

You can perform automated agent installation by running a template script that you download from the Azure portal. This script automates the download and installation of both agents.

This method requires that you have administrator permissions on the machine to install and configure the agent. You can use the root account on Linux, or on Windows, you can join the local administrators group.

Connect machines at scale using a service principal

To connect the machines to Azure Arc for servers, you can use an Azure Active Directory service principal instead of using your privileged identity to interactively connect the machine. A service principal is a special, limited management identity that has the minimum permission necessary to connect machines to Azure using the azcmagent command. Using a service principal is safer than using a higher privileged account like a Tenant Administrator and follows access control security best practices. The service principal is only used during onboarding. For more information, refer to Connect hybrid machines to Azure at scale.

Installation using Windows PowerShell DSC

You can automate agent installation and configuration for a Windows computer by using Windows PowerShell Desired State Configuration (DSC), Windows PowerShell, the AzureConnectedMachine DSC Module and a service principal for onboarding. For more information, refer to How to install the Connected Machine agent using Windows PowerShell DSC.

Manage VM extensions

Azure Arc for servers enables you to deploy Azure VM extensions to non-Azure Windows and Linux VMs, providing a consistent extension management experience between Azure and non-Azure VMs. VM extensions allow you to:

  • Use Azure Automation State Configuration to centrally store configurations and maintain the desired state of Arc enabled servers through the DSC VM extension.
  • Collect log data for analysis with Azure Monitor Logs enabled through the Log Analytics agent VM extension.
  • Analyze the performance of your Windows and Linux VMs using Azure Monitor and monitor their processes and dependencies on other resources and external processes.
  • Download and execute scripts on Arc enabled servers using the Custom Script extension.

For more information, refer to Virtual machine extension management with Azure Arc for servers.

Implement Azure Policy Guest Configuration

Azure Policy Guest Configuration can audit settings inside a machine, both for machines running in Azure and Arc enabled servers. For example, you can audit settings such as:

  • Operating system configuration
  • Application configuration or presence
  • Environment settings

There are several Azure Policy built-in definitions for Azure Arc. These policies provide auditing and configuration settings for both Windows and Linux-based machines.

Implement Update Management

You can perform update management for Arc enabled servers. Update management in Azure Automation enables you to manage operating system updates and quickly assess the status of available updates on all agent machines. You can also manage the process of installing required updates for servers.

Implement Change Tracking and Inventory

You can use Azure Automation Change Tracking and Inventory for Arc enabled servers to determine what software is installed in your environment. You can collect and observe inventory for software, files, Linux daemons, Windows services, and Windows Registry keys on your computers. Tracking the configurations of your machines can help you pinpoint operational issues across your environment and better understand the state of your machines.

Implement Azure Monitor

You can use Azure Monitor to monitor your VMs, virtual machine scale sets, and Azure Arc machines at scale. Azure Monitor analyzes the performance and health of your Windows and Linux VMs and monitors their processes and dependencies on other resources and external processes. It includes support for monitoring performance and application dependencies for VMs that are hosted on-premises or in another cloud provider.

Implement Azure Sentinel

You can use Azure Sentinel to deliver intelligent security analytics and threat intelligence across the enterprise, providing a single solution for alert detection, threat visibility, proactive hunting, and threat response. Azure Sentinel is a scalable, cloud-native, security information event management (SIEM) and security orchestration automated response (SOAR) solution that enables several scenarios including:

  • Collect data at cloud scale across all users, devices, applications, and infrastructure, both on-premises and in multiple clouds.
  • Detect previously undetected threats and minimize false positives.
  • Investigate threats with artificial intelligence and hunt for suspicious activities at scale.
  • Respond to incidents rapidly with built-in orchestration and automation of common tasks.

Topology and network considerations

The Connected Machine agent for Linux and Windows communicates outbound securely to Azure Arc over TCP port 443. If the machine connects through a firewall or proxy server to communicate over the internet, review the required URLs and service tags found on the Azure Arc Agent Networking configuration page.

Availability considerations

  • In most cases, the location you select when you create the installation script should be the Azure region geographically closest to your machine's location. The rest of the data will be stored within the Azure geography containing the region you specify, which might also affect your choice of region if you have data residency requirements. If an outage affects the Azure region to which your machine is connected, the outage will not affect the Arc enabled server, but management operations using Azure might not be able to complete. For resilience in the event of a regional outage, if you have multiple locations which provide a geographically-redundant service, it's best to connect the machines in each location to a different Azure region.
  • Ensure that Azure Arc is supported in your regions by checking supported regions.
  • Ensure that services referenced in the Architecture section are supported in the region to which Azure Arc is deployed.

Manageability considerations

  • Consult the list of supported operated systems on the Azure Arc agent overview page.
  • Before configuring your machines with Azure Arc for servers, you should review the Azure Resource Manager subscription limits and resource group limits to plan for the number of machines to be connected.

Security considerations

  • Appropriate role-based access control (RBAC) access should be managed for Arc enabled servers. To onboard machines, you must be a member of the Azure Connected Machine Onboarding role. To read, modify, re-onboard, and delete a machine, you must be a member of the Azure Connected Machine Resource Administrator role.
  • You can use Azure Policy to manage security policies across your Azure VMs and Arc enabled servers including implementing security policies in Azure Security Center. A security policy defines the desired configuration of your workloads and helps ensure you're complying with the security requirements of your company or regulators. Security Center policies are based on policy initiatives created in Azure Policy.

Cost considerations