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ARM processors have a new friend and his name is VMware ESXi

One of the most striking announcements at VMworld 2018 was the introduction of ARM architecture support for VMware’s emblematic hypervisor ESXi. It’s been a while now that ARM-powered servers and devices made their way in the enterprise IT market, so what is the goal of running ESXi on ARM, and is this targeting data center use cases?

VMware clearly stated during their presentation that their goal is to currently provide high availability features such as VMware HA (High Availability) and VMware FT (Fault Tolerance) to infrastructures located at the network’s edge.

This is a move that makes sense considering devices located at the network edge are becoming more and more “intelligent”, or better formulated “more connected”. Requirements are moving from single-board circuits with limited functionality into small-scale, “micro” data centers that are versatile enough to run multiple applications. This makes virtualization a great use case, however until now mainstream virtualization as we know it was mainly limited to the x86 architecture. While broadly available and cheap, x86 architectures are far from being optimized from a power consumption standpoint, an area where they are flatly beaten by their ARM counterparts.

Another consideration is the form factor, which is pretty much standardized in the x86 world. While TECHunplugged is not saying that vendors will come up with exotic form factors, it should be understood that “edge computing” embraces a really broad set of use cases where a rackmount design may not be optimal. It may be necessary to run an edge computing platform inside a modern electric/hybrid car architecture, inside public city equipment, under water, etc.

To date not much has been said about this new ESXi release for ARM. It is just known that there is cluster running somewhere, powered by Cortex-A72 processors. TECHunplugged expects that just like it’s big brother ESXi emulates the x86 instruction set, this version will emulate the ARM RISC instruction set. Nothing has been said of any potential portability or compatibility between x86 workloads and ARM workloads. Our uneducated guess is that ESXi-ARM will only support ARM-based VMs (such as Linux or Windows implementations of ARM), leaving any potential emulation at the OS layer.

What VMware also said is that this is (for now) strictly limited to edge computing use cases. At TECHunplugged, we see no compelling rationale to restrict ESXi-ARM to edge computing, since rackmount ARM servers for the data center are already a thing. Furthermore, multiple vendors engaged in HPC projects are already advertising (and implementing) ARM-based clusters as an energy/cost efficient solution.

For further reading, we recommend this article from our friend Enrico Signoretti.