In an Active Directory Environment, we keep additional domain controllers to improve resiliency. In this way, if one domain controller fails it will not make a big impact. We can further improve the resiliency of infrastructure by keeping an additional domain controller and mission-critical servers in a different location. So, in the event of a site failure, we will still have a domain controller and mission-critical servers running on a remote location. When we create the Azure Active Directory Domain Services managed domain, we provide a unique domain name. In the back end, Azure will deploy two domain controllers with this unique domain in your selected Azure region. This setup is called a “replica set“. Now, to improve resiliency, we can create additional replica sets in other Azure regions.
Each replica set uses a virtual network. All these virtual networks must be peered to create a mesh network to support the replication between replica sets.
Azure Active Directory Domain Services replica sets have the following characteristics.
• This feature is still in the preview stage.
• Each replica set contains the same data. You can’t use different domains for different replica sets.
• All replica sets will be placed in the same Active Directory site. Because of that the replication between replica sets is faster.
• All replica sets should create under the same subscription. You cannot have replica sets between different subscriptions.
• In the preview, you can have up to four replica sets.
• Replica sets only ensure the availability of the authentication services. But to use the full benefits of it, you need to consider how your Azure VMs, applications will work during a site failure.
In this demo, I am going to demonstrate how to create a replica set of existing Azure Active Directory Domain Services managed domain.
In my current setup, I already have Azure Active Directory Domain Services managed domain configured.
This is using REBELVN1 virtual network and aadds-subnet.
REBELVN1 virtual network is set up under REBELRG1 resource group. This resource group is using “East US” Azure region. The Virtual network is using 10.0.0.0/16 address space. It has two subnets.
vmsubnet – 10.0.2.0/24 for virtual machines
aadds-subnet – 10.0.0.0/24 for Azure Active Directory Domain Services managed domain
In this demo, I am going to create a new virtual network in “West US” Azure region. Later this will be used to host the additional replica test. [Read more…] about Step-by-Step Guide: Azure Active Directory Domain Services resiliency with replica sets