Windows Server 2008 and Windows Server 2008 R2 Operating system reached the end of their support cycle on the 14th of January 2020. Because of this many organizations wanted to migrate away from these legacy operating systems. End-of-life operating systems have a direct impact on various industry compliances, IT audits, Penetration tests, and so on. Even business does not have a business requirement to upgrade, end of life operating system leaves no choice but to upgrade.
In the past, I did a similar blog post covering migration AD from Windows Server 2008 to Windows Server 2016. Microsoft released Windows Server 2022 recently (Aug 2021) and I thought it good to demonstrate how we can migrate AD from 2008 R2 to the newest. AD migrations from other operating systems (newer than Windows Server 2008R2) also follow a similar process.
What is New in Active Directory?
AD DS’ improvements are bond to its forest and domain functional levels. Upgrading the operating system or adding domain controllers that run Windows Server 2022 to an existing AD infrastructure isn’t going to upgrade the forest and domain functional levels automatically. We need to upgrade it manually once older domain controllers are decommissioned. There was a big difference with Windows Server 2019 when it comes to forest and domain functional levels. With each and every Windows Server release up to Windows Server 2016, had a new forest and domain functional level. But with Windows Server 2019 there were NO new forest or domain functional levels. It is the same with Windows Server 2022. The maximum forest and domain functional level we can choose still is Windows Server 2016.
Active Directory Domain Services was first introduced to the world with Windows Server 2000. For more than 21 years, AD DS helps organizations to manage digital identities. However, the modern access management requirements are complicated. Businesses are using more and more cloud services now. The majority of the workforce is still working from home and accessing sensitive corporate data via unsecured networks. Most software vendors are moving into SaaS model. Cybercrimes are skyrocketing and identity protection is at stake. To address these requirements, we need to go beyond legacy access management. Azure Active Directory is a cloud-based, managed, Identity as a Service (IDaaS) provider, which can provide world-class security, strong authentication, and seamless collaboration. So, it does make sense why there are no significant changes to on-premises AD anymore.
One of the key themes of Windows Server 2022 is “security”. Advanced multi-layer security in Windows Server 2022 provides comprehensive protection against modern threats. This also adds an additional layer of security to roles run on Windows Server 2022 including Active Directory. For more details about these security features please refer to https://docs.microsoft.com/en-us/windows-server/get-started/whats-new-in-windows-server-2022
Active Directory Migration Check List
Migrating FSMO roles to a new server and upgrading forest and domain functional levels doesn’t take more than few minutes but when it comes to migration there are few other things we need to consider. Therefore, I have summarized the AD DS Migration process with the following checklist.
- Evaluate the business requirements for Active Directory migration.
- Perform an audit on the existing Active Directory infrastructure to verify its health.
- Create a detailed implementation plan.
- Prepare the physical/virtual resources for the domain controller.
- Install Windows Server 2022 Standard/Datacenter.
- Patch the servers with the latest Windows updates.
- Assign a dedicated IP address to the domain controller.
- Install the AD DS role.
- Migrate the application and server roles from the existing domain controllers.
- Migrate the FSMO roles to the new domain controllers.
- Add new domain controllers to the existing monitoring system.
- Add new domain controllers to the existing DR solution.
- Decommission the old domain controllers (all).
- Raise the domain and forest functional levels.
- Perform ongoing maintenance (Group Policy review, new-feature implementations, identifying and fixing Active Directory infrastructure issues, and more)
Most Common Questions About Active Directory Migrations
Below I listed some of the most common questions about AD migration,
- Can I keep the same IP address for the PDC? Yes, you can. Active Directory fully supports IP address changes. Once FSMO role migration is completed, you can swap the IP addresses of Domain Controllers.
- Can I downgrade forest/domain functional levels? If you required you can do so but this is not a recommended approach. From Windows Server 2008 R2, we can downgrade forest/domain functional levels.
- Do I need to migrate the DNS role? No, it is part of the AD. When you add a new domain controller, you can make it as a DNS server too.
- Do I need to change SYSVOL replication from FRS to DFS? If your domain is built based on Windows server 2008 or Windows Server 2008 R2, you are already using DFS for SYSVOL replication. If you originally migrated from Windows server 2003, it’s more likely you are still using FRS. In that case, before migration, you need to change the SYSVOL replication method from FRS to DFS. I already have a blog post covering this topic https://www.rebeladmin.com/2015/04/step-by-step-guide-for-upgrading-sysvol-replication-to-dfsr-distributed-file-system-replication/
- Can I keep Windows 2008 R2 Domain Controllers and upgrade forest and domain functional level to Windows Server 2016? No, you can’t. Before forest and domain functional level upgrade, you need to decommission Windows server 2008 R2 domain controllers.
Design topology
As per the following diagram, the rebeladmin.net domain has two domain controllers:
As explained in the above illustration, The FSMO role holder DC08 is a Windows Server 2008 R2 Domain Controller. The domain and forest functional levels currently operate in Windows Server 2008 R2. A new domain controller with Windows Server 2022(DC22) will be introduced and will be the new FSMO role holder for the domain. Once the FSMO role migration is complete, the domain controller running Windows Server 2008 R2 will be decommissioned. After that, the forest and domain functional levels will be raised to Windows Server 2016.
When you introduce new domain controllers to existing infrastructure, it is recommended that you introduce the forest root level first and then go to the domain tree levels. [Continue reading] about Step-by-Step Guide: Active Directory Migration from Windows Server 2008 R2 to Windows Server 2022
