Making of Nutanix AHV Hypervisor a Top Alternative

In this Tech Barometer podcast, former Nutanix engineers Mike Cui and Greg Smith describe the genesis of the Nutanix AHV hypervisor and the confluence of industry changes feeding its growing success.

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Transcript:

Mike Cui: Well, this is where we have to go into the story.

Greg Smith: Maybe Mike, since you were there before me, you can provide some of the context and the lead up for what happened.

Mike Cui: I came up with an idea and I convinced a whole bunch of people we should do this. Not that we should do this, but we could actually do this. It’s possible.

Greg Smith: As I remember it, when I joined, I thought I was joining the Stargate team to work on storage and performance tuning, and Mike pulled me aside and said, well, we need this one change in Stargate, but then you should really go and work on making KVM a product.

Jason Lopez: Even in IT, life happens. Innovations often emerge when you don’t plan them, and that’s what happened to Mike Cui and Greg Smith. Today, Mike is a principle engineer at Annapurna Labs and Greg works at Foxglove Technologies. In 2013, they were at Nutanix and back then the market wasn’t expecting another hypervisor.

Kanchan Mirani: It was very much VMware who created that category.

Jason Lopez: Kanchan Murani is senior director of strategic marketing at Nutanix. She said VMware was a pioneer of the hypervisor and grew into an industry leader.

Kanchan Mirani: At some point, VMware was so far ahead. It was really the only hypervisor out there that any enterprise would seriously consider.

Jason Lopez: Until AHV.

[Related: IT Resiliency: Running Two Different Hypervisors]

Mike Cui: I had an idea for something like AHV.

Greg Smith: I guess we were the creators of AHV. Yeah.

Mike Cui: This is where it’s not like we had a grand plan. It is tied with the story of how we accidentally got our first customer and what we had to do to solve the problem for this customer, and then eventually evolving into a full-blown product.

Jason Lopez: Before delving into the story of how AHV came to be, let’s look at what it is. Nutanix AHV, or the Acropolis Hypervisor, is virtualization software that enables it to run VMs. It’s a core component of the Nutanix Cloud platform which is ever evolving. With the latest update, as of mid 2025, AHV is at version 10.0. Here’s how Kanchan describes it.

Kanchan Mirani: It’s a pretty core infrastructure software piece, which helps IT teams manage all their resources, essentially. Think of an IT team that’s getting requests from all different departments and lines of business who want to run their specific applications and they’re trying to manage all their resources. Now, imagine if they had to put in actual boxes for each request that each line of business came to them with, versus having a sort of bank of resources, which they’re able to allocate really easily without actually doing physical connections and so on and so forth. So virtualization helps you do that because it makes it software based. You can give somebody a machine, which is a fractional part of a server and say, here, go develop on this, and you can do that all with software through the hypervisor.

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Jason Lopez: Back in 2011, AHV didn’t exist, but at the time, Mike was on a team pushing to get the company’s first version of its Power App out. Power App was designed to provide a simple and efficient way for users to create, deploy and manage virtual machines.

Mike Cui: We shipped it and then throughout 2012 things were mostly chill. Like people can finally relax.

Jason Lopez: A year later, Nutanix decided to expand support beyond VMware to other hypervisors such as Microsoft’s, HyperV and kernel based virtual machines or KVMs, the open source virtualization technology for Linux operating systems.

Mike Cui: We installed it. It was our first attempt at making something work in Japan. The customers were asking us, how does this KVM thing work? Where’s your user interface? I’m like, we don’t have any.

Jason Lopez: Mike thought the customer wanted KVMs because they knew how to use them, but they didn’t know anything about them.

Mike Cui: We’ll go back and work on it, and I tried to build something during the same trip. The night before I was flying back, we had a Friday all-hands meeting. We just did a deal with a three-letter government agency, and this deal was going to be all KVM and this is me still sitting here in Japan, asking: like what? I just had to explain to our first customer that we have nothing.

[Related: Search for VMware Alternatives That Meet Existing and Future Needs]

Jason Lopez: Mike saw another customer was eager to run Nutanix on KVM and knew it was high time to create that GUI.

Mike Cui: Right about when we closed the deal, they realized they didn’t have any money left to buy ESX licenses.

Jason Lopez: The customer in Japan could no longer pay for the VMware hypervisor because they had spent their budget on buying new Nutanix software and new flash memory powered hardware. As Mike recalls, they held Nutanix in such high regard. They believed it was possible to move from ESX to the KVM. They were all in on Mike and his team to get them up and running on the new high hypervisor.

Greg Smith: There’s no way that any customer in the modern era would’ve accepted this as a solution, right? But because they had no experience with virtualization, we got away with a lot, and so this really scrappy, scripted, hacked up solution. How much time do we spend on that? A couple of weeks, right? 

Mike Cui: It was all you. I don’t know (chuckles)

Greg Smith: Yeah, it wasn’t more than a couple of weeks. The first week I spent on doing the Stargate code, a snapshot from NFS to SCSI, and then I think it was two or three weeks working on the scripts and then you went on vacation for two weeks.

Mike Cui: Oh, yeah. I went to try that.

Greg Smith: So I’m brand new at the company. Like here I’m defending this…thing that did not feel like a product at all.

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Kanchan Mirani: When Nutanix came along, we essentially created AHV from an open source base to begin. At that point, we were trying to optimize what’s possible in the field of software-defined computing. We had the storage piece. We wanted to extend it to computing, which is where the hypervisor came in, and over time we developed it into a pretty world-class hypervisor that was very competitive with what was out there.

Jason Lopez: AHV became a real alternative to VMware. Over time, this evolved with steady but slow adoption, but the latest chapter in the AHV story started when Broadcom acquired VMware.

Kanchan Mirani: We’ve always supported freedom of choice. So in our platform, we support ESXi, which is VMware’s hypervisor as well as our own AHV. And we’ve seen a steady growth in the percentage of our customers who are using AHV. We’ve seen a steady growth since the beginning, but it definitely got a bump and continues to grow after the acquisition, so that’s an indicator of where the customers are putting their choices now.

Jason Lopez: Between August, 2023 and April, 2025, the adoption of AHV as a percentage of cores grew significantly, which means customers run more of their Nutanix powered IT operations on the AHV hypervisor. Greg said simplicity and optionality are built into the core of AHV.

Greg Smith: Part of what made VMware such a great product to use as an engineer was like all of these nerd knobs that you could just tweak out to the nth degree, but it led to a very complicated experience, especially when you had to consider things like upgrades. So we decided very deliberately to try and sidestep all of that by presenting a very simple interface that we expected never to change. That was a huge part of our philosophy. For a long time, we thought that the surefire win for AHV as a solution was like test and dev. We had made it work for test and dev internally, and we said: Look, we know that this works.

Jason Lopez: Greg and Mike say there was some luck, too. You can have the right philosophy but the wrong timing, and in their story, they didn’t think they were building a full-blown marketable product, but a solution for a single customer.

Mike Cui: I did not expect AHV to have that level of success. I just feel like we were building something and we got it to work. That was already a huge accomplishment.

Greg Smith: It just had a knack of being in the right place at the right time with the right things going on all around it, various things from the open source world that we were able to take advantage of.

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