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Study Notes: NSX Virtualization

from the Hydra High Council Apr 9th 2019

Learning NSX doesn't have to be difficult. If you are new to NSX, this series will start from the beginning and will explain things along the way, in short, but easy to follow bite-sized chunks.


Virtualization is the first concept we need to really understand. It is primarily about decoupling. With virtual machines, the operating system and applications are separated (decoupled) from the hardware.

Between the two is an abstraction layer called the hypervisor, the kernel. If the operating system needs a resource, like memory or compute cycles, it makes a simple call to the hypervisor. The OS no longer needs to know any of the underlying complexities involving the hardware.

Software/Hardware vs Mind/Body

Imagine if this were a bad science fiction movie, with you in the lead role. The doctors have figured out how to separate your mind from your body (your operating system, from your hardware). Instead of sending nerve impulses all the way through your body to perform an action, your mind only needs to send impulses to a nearby interface. This simple interface is used for all actions. That interface is like the hypervisor.

Control Plane and Data Plane

The mind, in this analogy, does the controlling. The body does the doing. The operating system is the control plane, what does the controlling, the logic of deciding what is to be done. The NIC does the work as instructed, sending the data. It is referred to as the data plane.

By separating the operating system with its applications (all the software) from the compute resources (all the hardware) we gain the ability to have that operating system treated like an independent bunch of files. As files, they can be copied, moved, deleted, backed up, and restored. We also are no longer tied to a 1:1 ratio of one operating system per physical host machine. Within one physical host, you could have many virtual machines. Each would then be given a dedicated portion of the CPU and memory.

Copy That, Move This

Because we can copy, that means we can deploy a ready-made operating system with its application very quickly without having to install the operating system or install the application. A great use case is to use the copy as a backup.

Because we can move, this means that if a virtual machine is having performance issues in one part of the network, it's possible to move it to a different host where more resources are available.

Virtualizing Networks

VMware NSX takes this same approach and virtualizes networks. It creates a wholly different virtual network and overlays it on top of the physical network.

It uses virtual switches, virtual routers, virtual load balancers, and virtual firewalls. Like virtual machines, these virtual networking components separate the software and hardware, the control plane from the data plane.

Network Agility

As we go through this series to learn more about NSX, we'll get into a multitude of benefits and features. For now, keep in mind that the same things we can do with a virtual machine (copy, move, delete, backup, and restore), we can now do with entire virtual networks.

Study Terms
decoupling - separating software from hardware
control plane - logic that does the controlling, decisions on where to send data
data plane - does the doing, sends the data based on what the control plane decided
NSX - VMware's product for virtualizing networks; virtualizes routers, switches, load balancers, and firewalls