Getting Started with Group Managed Service Accounts

Applies to: Windows Server 2022, Windows Server 2019, Windows Server 2016

In this article, learn how to enable and use group Managed Service Accounts in Windows Server.

Authentication protocols supporting mutual authentication such as Kerberos can't be used unless all the instances of the services use the same principal. For example, when a client computer connects to a service that uses load balancing or another method where all the servers appear to be the same service to the client. Meaning each service has to use the same passwords or keys to prove their identity. Group Managed Service Accounts (gMSA) are a type of account that can be used with multiple servers. A gMSA is a domain account that can be used to run services on multiple servers without having to manage the password. The gMSA provides automatic password management and simplified service principal name (SPN) management, including delegation of management to other administrators.

Services can choose the principal to use. Each principal type supports different services and has different limitations.

A Windows computer account, a Windows standalone Managed Service Account (sMSA), or virtual accounts can't be shared across multiple systems. When you use virtual accounts, the identity is also local to the machine and not recognized by the domain. If you configure one account for services on server farms to share, you would have to choose a user account or a computer account apart from a Windows system. Either way, these accounts don't have the capability of single-point-of-control password management. Without password management, each organization needs to update keys for the service in Active Directory and distribute these keys to all instances of those services.

With Windows Server, services and service administrators don't need to manage password synchronization between service instances when using group Managed Service Accounts (gMSA). You create the gMSA in AD and then configure the service that supports Managed Service Accounts. Use of the gMSA is scoped to any machine that is able to use LDAP to retrieve the gMSA's credentials. You can create a gMSA using the New-ADServiceAccount cmdlets that are part of the Active Directory module. The following services support the service identity configuration on the host.

• Same APIs as sMSA, so products that support sMSA support gMSA

• Services that use Service Control Manager to configure logon identity

• Services that use the IIS manager for application pools to configure identity

• Tasks using Task Scheduler.

Prerequisites

The following table lists the operating system requirements for Kerberos authentication to work with services using gMSA. The Active Directory requirements are listed after the table.

A 64-bit architecture is required to run the Windows PowerShell commands used to administer group Managed Service Accounts.

Operating system

Active Directory Domain Services

Group Managed Service Accounts have the following requirements in Active Directory Domain Services (AD DS).

• The Active Directory domain and forest functional level must be Windows Server 2012 or later. To learn more about updating the schema, see Raising the Active Directory domain and forest functional levels.

• If you're managing the service host permission to use gMSA by group, then new or existing security group.

• If managing service access control by group, then new or existing security group.

• The Key Distribution Services (KDS) Root Key for Active Directory must be created in the domain. The result of its creation can be verified in the KdsSvc Operational log, Event ID 4004. To learn more about creating the KDS root key, see Create the Key Distribution Services KDS Root Key.

For instructions how to create the key, see Create the Key Distribution Services KDS Root Key. Microsoft Key Distribution Service (kdssvc.dll) the root key for AD.

Deploying a new server farm

The process of creating and managing a server farm using the gMSA feature typically involves the following tasks.

• Deploying a new server farm

• Adding member hosts to an existing server farm

• Decommissioning member hosts from an existing server farm

• Decommissioning an existing server farm

• Removing a compromised member host from a server farm if necessary

When the service administrator deploys a new server farm, they need to determine the following information.

• The service supports using gMSAs

• The service requires inbound or outbound authenticated connections

• The computer account names for the member hosts for the service using the gMSA

• The NetBIOS name for the service

• The DNS host name for the service

• The Service Principal Names (SPNs) for the service

• The password change interval (default is 30 days)

Create group Managed Service Accounts

You can create a gMSA only if the forest schema is Windows Server 2012 or later. You must also deploy the KDS Root Key for Active Directory, and have at least one Windows Server 2012 or later domain controller in the domain where you want to create a gMSA.

Membership in Domain Admins or the ability to create msDS-GroupManagedServiceAccount objects, is the minimum required to complete the following procedures.

To create a gMSA using PowerShell, follow these steps.

1. On the Windows Server 2012 domain controller, run Windows PowerShell from the Taskbar.

2. At the command prompt for the Windows PowerShell, type the following commands, and then press ENTER. (The Active Directory module loads automatically.)

   New-ADServiceAccount [-Name] <string> -DNSHostName <string> [-KerberosEncryptionType <ADKerberosEncryptionType>] [-ManagedPasswordIntervalInDays <Nullable[Int32]>] [-PrincipalsAllowedToRetrieveManagedPassword <ADPrincipal[]>] [-SamAccountName <string>] [-ServicePrincipalNames <string[]>]

   Note

   A value for the -Name parameter is always required (whether you specify -Name or not), with -DNSHostName, -RestrictToSingleComputer, and -RestrictToOutboundAuthentication being secondary requirements for the three deployment scenarios.

   Parameter	String	Example
   Name	Name of the account	ITFarm1
   DNSHostName	DNS host name of service	ITFarm1.contoso.com
   KerberosEncryptionType	Any encryption types supported by the host servers	None, RC4, AES128, AES256
   ManagedPasswordIntervalInDays	Password change interval in days (default is 30 days if not provided)	90
   PrincipalsAllowedToRetrieveManagedPassword	The computer accounts of the member hosts or the security group that the member hosts are a member of	ITFarmHosts
   SamAccountName	NetBIOS name for the service if not same as Name	ITFarm1
   ServicePrincipalNames	Service Principal Names (SPNs) for the service	http/ITFarm1.contoso.com/contoso.com, http/ITFarm1.contoso.com/contoso, http/ITFarm1/contoso.com, http/ITFarm1/contoso, MSSQLSvc/ITFarm1.contoso.com:1433, MSSQLSvc/ITFarm1.contoso.com:INST01

   Important

   The password change interval can only be set during creation. If you need to change the interval, you must create a new gMSA and set it at creation time.

   For example, to create a new gMSA called ITFarm1 for the group use the following command. The gMSA allows the service to use the Kerberos encryption types RC4, AES128, and AES256. The service is allowed to use the SPNs http/ITFarm1.contoso.com/contoso.com, http/ITFarm1.contoso.com/contoso, http/ITFarm1/contoso.com, and http/ITFarm1/contoso.

   Enter the command on a single line, even though they might appear word-wrapped across several lines here because of formatting constraints.

    New-ADServiceAccount ITFarm1 -DNSHostName ITFarm1.contoso.com -PrincipalsAllowedToRetrieveManagedPassword ITFarmHosts$ -KerberosEncryptionType RC4, AES128, AES256 -ServicePrincipalNames http/ITFarm1.contoso.com/contoso.com, http/ITFarm1.contoso.com/contoso, http/ITFarm1/contoso.com, http/ITFarm1/contoso
   

Membership in Domain Admins, Account Operators, or ability to create msDS-GroupManagedServiceAccount objects, is the minimum required to complete this procedure. For detailed information about using the appropriate accounts and group memberships, see Active Directory security groups.

To create a gMSA for outbound authentication only using PowerShell, follow the steps.

1. On the Windows Server 2012 domain controller, run Windows PowerShell from the Taskbar.

2. At the command prompt for the Windows PowerShell Active Directory module, use the following command.

   New-ADServiceAccount [-Name] <string> -RestrictToOutboundAuthenticationOnly [-ManagedPasswordIntervalInDays <Nullable[Int32]>] [-PrincipalsAllowedToRetrieveManagedPassword <ADPrincipal[]>]

   The following example creates a gMSA using the parameters in the table.

   Parameter	String	Example
   Name	Name the account	ITFarm1
   ManagedPasswordIntervalInDays	Password change interval in days (default is 30 days if not provided)	75
   PrincipalsAllowedToRetrieveManagedPassword	The computer accounts of the member hosts or the security group that the member hosts are a member of	ITFarmHosts

   Important

   The password change interval can only be set during creation. If you need to change the interval, you must create a new gMSA and set it at creation time.

   The example command using these parameters as follows.

   New-ADServiceAccount ITFarm1 -RestrictToOutboundAuthenticationOnly - PrincipalsAllowedToRetrieveManagedPassword ITFarmHosts$
   

Configure service identity application service

To configure the services in Windows Server, see the following articles:

• IIS application pool

  For more information, see Specify an Identity for an Application Pool (IIS 7).

• Windows Services

  For more information, see Services.

• Tasks

  For more information, see the Task Scheduler Overview.

Other services could support gMSA. See the appropriate product documentation for details on how to configure those services.

Add member hosts to an existing server farm

If using security groups for managing member hosts, add the computer account for the new member host to the security group (that the gMSA's member hosts are a member of) using one of the following methods.

Membership in Domain Admins, or the ability to add members to the security group object, is the minimum required to complete these procedures.

• Method 1: Active Directory Users and Computers

  For procedures how to use this method, see Add a computer account to a group using the Windows interface, and Manage Different Domains in Active Directory Administrative Center.

• Method 2: dsmod

  For procedures how to use this method, see Add a computer account to a group using the command line.

• Method 3: Windows PowerShell Active Directory cmdlet Add-ADPrincipalGroupMembership

  For procedures how to use this method, see Add-ADPrincipalGroupMembership.

If using computer accounts, find the existing accounts and then add the new computer account.

Membership in Domain Admins, Account Operators, or ability to manage msDS-GroupManagedServiceAccount objects, is the minimum required to complete this procedure. For detailed information about using the appropriate accounts and group memberships, see Local and Domain Default Groups.

Add member hosts using PowerShell

1. On the Windows Server 2012 domain controller, run Windows PowerShell from the Taskbar.

2. At the command prompt for the Windows PowerShell Active Directory module, type the following commands, and then press ENTER:

   Get-ADServiceAccount [-Identity] <string> -Properties PrincipalsAllowedToRetrieveManagedPassword

3. At the command prompt for the Windows PowerShell Active Directory module, type the following commands, and then press ENTER:

   Set-ADServiceAccount [-Identity] <string> -PrincipalsAllowedToRetrieveManagedPassword <ADPrincipal[]>

The following example adds a member to a server farm using the parameters in the table.

The following example gets the current members of the farm ITFarm1.

Get-ADServiceAccount [-Identity] ITFarm1 -Properties PrincipalsAllowedToRetrieveManagedPassword

The following example adds member hosts to an existing server farm ITFarm1.

Set-ADServiceAccount [-Identity] ITFarm1 -PrincipalsAllowedToRetrieveManagedPassword Host1$,Host2$,Host3$

Update the group Managed Service Account properties

Membership in Domain Admins, Account Operators, or the ability to write to msDS-GroupManagedServiceAccount objects, is the minimum required to complete these procedures.

Open the Active Directory Module for Windows PowerShell, and set any property by using the Set-ADServiceAccount cmdlet.

For detailed information how to set these properties, see Set-ADServiceAccount in the TechNet Library or by typing Get-Help Set-ADServiceAccount at the Active Directory module for Windows PowerShell command prompt and pressing ENTER.

Remove a member hosts from an existing server farm

Membership in Domain Admins, or ability to remove members from the security group object, is the minimum required to complete these procedures.

If using security groups for managing member hosts, remove the computer account for the decommissioned member host from the security group that the gMSA's member hosts are a member of using either of the following methods.

• Method 1: Active Directory Users and Computers

  For procedures how to use this method, see Delete a Computer Account using the Windows interface, and Manage Different Domains in Active Directory Administrative Center.

• Method 2: drsm

  For procedures how to use this method, see Delete a Computer Account using the command line.

• Method 3: Windows PowerShell Active Directory cmdlet Remove-ADPrincipalGroupMembership

  For detailed information how to remove a member from the group managed service account, see Remove-ADPrincipalGroupMembership in the TechNet Library or by typing Get-Help Remove-ADPrincipalGroupMembership at the Active Directory module for Windows PowerShell command prompt and pressing ENTER.

If listing computer accounts, retrieve the existing accounts and then add all but the removed computer account.

Membership in Domain Admins, Account Operators, or ability to manage msDS-GroupManagedServiceAccount objects, is the minimum required to complete this procedure. For detailed information about using the appropriate accounts and group memberships, see Local and Domain Default Groups.

Remove member hosts using PowerShell

1. On the Windows Server 2012 domain controller, run Windows PowerShell from the Taskbar.

2. At the command prompt for the Windows PowerShell Active Directory module, type the following commands, and then press ENTER:

   Get-ADServiceAccount [-Identity] <string> -Properties PrincipalsAllowedToRetrieveManagedPassword

3. At the command prompt for the Windows PowerShell Active Directory module, type the following commands, and then press ENTER:

   Set-ADServiceAccount [-Identity] <string> -PrincipalsAllowedToRetrieveManagedPassword <ADPrincipal[]>

The following example removes a member to a server farm using the parameters in the table.

The following example gets the current members of the farm ITFarm1.

Get-ADServiceAccount [-Identity] ITFarm1 -Properties PrincipalsAllowedToRetrieveManagedPassword

The following example removes member hosts from an existing server farm ITFarm1.

Set-ADServiceAccount [-Identity] ITFarm1 -PrincipalsAllowedToRetrieveManagedPassword Host1$,Host3$

Remove a group Managed Service Account from the system

Remove the cached gMSA credentials from the member host using Uninstall-ADServiceAccount or the NetRemoveServiceAccount API on the host system.

Membership in Administrators, or equivalent, is the minimum required to complete these procedures.

Remove a gMSA using PowerShell

1. On the Windows Server 2012 domain controller, run Windows PowerShell from the Taskbar.

2. At the command prompt for the Windows PowerShell Active Directory module, type the following commands, and then press ENTER:

   Uninstall-ADServiceAccount <ADServiceAccount>

   The following example uninstalls an Active Directory managed service account from a computer.

   Uninstall-ADServiceAccount ITFarm1
   

For more information about the Uninstall-ADServiceAccount cmdlet, at the Active Directory module for Windows PowerShell command prompt, type Get-Help Uninstall-ADServiceAccount, and then press ENTER, or see the information on the TechNet web at Uninstall-ADServiceAccount.

Related content

• Group Managed Service Accounts Overview