Azure Stack HCI Learning Path – Part 1 – What is HCI?

Before we start talking about Azure Stack HCI, let’s start with just HCI. HCI or “Hyperconverged Infrastructure” is a recent datacenter technology that lets you modernize and minimize your hardware footprint. A more “traditional” datacenter has different tiers of hardware (compute, storage and network) externally connected to each other, and as you can imagine this not only takes up a lot of physical space, but also introduces many related technical and management problems.

Datacenter technologies have been evolving towards a more compact and easier-to-manage approach over the last few years, and HCI is gaining traction a lot recently.

So what is HCI and how is it difference than a traditional datacenter? I’ve tried to list out the differences I’ve found in a table here:

Traditional Infrastructure	Hyperconverged Infrastructure
Contains  discreet compute, storage, and network hardware tiers.	A single appliance combines compute, storage, and network elements leveraging software defined approach.
Each tier is “siloed” – usually independently managed and from independent vendors.	Since there’s a single appliance, it is delivered as a productized solution by a single verified OEM.
Difficult to scale up. Requires careful manual reconfiguration.	Easy to add more capacity to existing deployments.
More admin overhead required since there are multiple tiers with multiple management planes.	Admin overhead is less since there’s less infrastructure and a single pane of management.
Difficult to set up for hybrid cloud deployments.	Integrates seamlessly with hybrid cloud model.
Less cost efficient as there’s more CAPEX investment.	More cost efficient as you can scale up and down easily and operate on OPEX investment.
More difficult and expensive to maintain as there are multiple points of failure.	Easier to maintain since multiple functions are converged together.
Longer and time-consuming BCDR process.	Easier and quicker BCDR with built in fault tolerance and replication.
Complex deployment model requires time and effort.	Very easy to deploy with minimal hardware reducing the time to stand up significantly.
Higher Cost of Entry.	Lower Cost of Entry, most HCI can start as small as just 2 servers.

Here’s a great pictorial representation I found here that shows the overall differences and benefits of using HCI over traditional infrastructure.

As you can see, a LOT less infrastructure to deal with, which makes life for everyone involved much easier 😉

Alright. So that’s HCI. Now that that’s out of the way, we can talk about Azure Stack HCI in particular. And in my research, this is the best I came up with.

“Azure Stack HCI is a purpose-built Operating System delivered as an Azure service that leverages Azure Arc tightly to provide you a modern, easy and hybrid IT management plane across your local or multi-cloud infrastructure.”

Wait a minute! Did I read that right? Did you just say AzS HCI is an Operating System? Sure did, and so you must be wondering, if it’s just an OS, where’d all that hardware mumbo jumbo come from? And that is a perfectly valid question.

Azure Stack HCI is an offering by Microsoft to run specialized management layer as an Azure service, but there are verified OEM partners such as Dell, that provide you the HCI hardware WITH the OS preinstalled on it as a productized offering that makes it much easier for the end user to purchase it and get going. Since the hardware and the software are shipped together, the vendor will help you with the initial setup and a single point of contact for everything related.

If you’re still unsure of what this means, there’s no reason to worry! We will surely revisit this later in the series. In my experience in reading through the Azure Stack HCI documentation, I quickly realized that you can’t properly understand Azure Stack HCI without a few other surrounding technologies that make up HCI. So we will turn our Azure Stack HCI cruise slightly left and first do some reading about these other background concepts first.

These are some of the topics we will visit next:

• Azure Arc
• Storage and cluster (S2D – Storage Spaces Direct)
• Software Defined Networking (SDN)

Once we are more familiar with these, we will circle back to Azure Stack HCI and dive deeper and that’s when all of the pieces will start falling into places perfectly.

See you in the next one!