When we talk about AD, we refer to it as a single service; however, AD DS is a collection of many other components such as DNS, group policies, and SYSVOL folder replication. Each of these components needs to operate well in order to run a healthy AD environment. Managing these components isn't easy; it requires investments in resources, time, and skills. As we can see, the success of identity infrastructure depends on these components. It is not just about service uptime and performance; security also plays a crucial role in this. The failure or compromise of these components/services can have a potential impact on the entire AD infrastructure.

Microsoft Windows Core and Nano Server also count as OSes. They don't have fancy GUIs or lots of defaults running, but they still do the job of an OS. They allow users to build systems from scratch according...