Alternatives to VMware: Nutanix

This is one of a series of posts looking at alternatives to VMware following the completion of the acquisition of the company by Broadcom. In this post, we investigate a pioneer of hyper-converged infrastructure, Nutanix, Inc.

Alternatives to VMware: Introduction

Background

Nutanix was founded in 2009 by Dheeraj Pandey, Ajeet Singh, and Mohit Aron, none of whom now work for the company. Pandey left sometime following the IPO to set up DevRev, while Aron and Singh left relatively early, founding Cohesity and ThoughtSpot, respectively. Nutanix raised a total of $312.2 million in financing, going public via IPO in September 2016. At the time of writing, the company is valued at approximately $11 billion.

The first platform developed by Nutanix was a distributed file system running in a set of virtual machines on VMware vSphere. The Nutanix Distributed File System (NDFS) provided the basis for implementing hyper-converged infrastructure, where the storage presented to individual virtual machines is taken from NDFS. The virtual instances running NFDS are known as CVMs or control virtual machines. They provide the management and control of storage as well as supporting the GUI and API/CLI interfaces.

In comparing Nutanix to VMware, we have determined seven aspects of private clouds as part of our analysis. These are the hypervisor, the platform, the ecosystem, commercials (licensing), deployment models, features, and migration & mobility. More details on these areas can be found in our introduction post here.

Hypervisor

The initial deployment of NFDS was based on VMware vSphere and, for some time, was the only hypervisor option. In June 2015, Nutanix announced Acropolis, a suite of features to deliver the Nutanix hyper-converged infrastructure platform. Acropolis included AOS, the Acropolis Operating System and AHV, the Acropolis Hypervisor. AHV is a type-1 hypervisor based on QEMU-KVM initially running on CentOS. With the introduction of AHV, customers could choose to implement an HCI platform without the dependence on VMware vSphere (the vTax, as Nutanix described it at the time).

The development and release of AHV is important as it marked the divergence away from a dependence on VMware. However, as reported in the Q3 FY2021 earnings announcements, only around 52% of active nodes were being deployed with AHV, which is still the split of AHV and non-AHV clusters today.

Nutanix now offers customers three deployment choices at the hypervisor level – VMware ESXi (as part of a vSphere deployment), AHV (as part of AOS) and Microsoft Hyper-V. However, clusters cannot be built with mixed hypervisor types except in a limited number of scenarios (such as where storage-only nodes are deployed).

One of the strengths of VMware vSphere is ESXi, which is a robust and reliable hypervisor platform. ESXi isn’t built on another operating system but runs a custom kernel called vmkernel. Owning the kernel enables VMware to develop features and functionality in a proprietary manner. However, KVM and QEMU are also robust and reliable solutions that have been available for many years (almost two decades for KVM). We will cover hypervisors in separate content.

Platform

Nutanix has extended and enhanced the original platform offering, which, over the years, has included a few name changes. Today, the Nutanix Cloud Platform (NCP) is comprised of five main components.

Nutanix Cloud Infrastructure – Acropolis and the AHV hypervisor and other virtual machine-level features and functionality, including the Nutanix Kubernetes Engine (NKE), networking (Flow) and Nutanix Cloud Clusters (NC2).
Nutanix Cloud Manager– the GUI and API/CLI to manage the infrastructure, including automation, Self Service (the Calm acquisition), Cost Governance (formerly Beam, from the Minjar acquisition).
Nutanix Unified Storage – the File Storage, Object Storage and Block Storage solutions, together with Mine Integrated Backup.
Nutanix Database Service – platform-as-a-service delivered databases, supporting common solutions including Microsoft SQL Server, Oracle, PostgreSQL, MongoDB, and MySQL.
End User Computing – until recently, VDI and Frame, however, Frame was sold off to private equity in May 2023.

Nutanix Cloud Clusters enables customers to deploy the Nutanix platform on bare-metal instances from either AWS or Microsoft Azure. This option is analogous to the VMware Cloud solutions that run vSphere on public cloud infrastructure.

Ecosystem

NCP matches the features of vSphere and the broader VMware ecosystem with solutions such as Flow for software-defined networking and security, and NKE, which aligns to Tanzu. Nutanix has been more advanced in storage solutions, delivering integrated storage with the initial deployment of NDFS. This has been extended to offer file and object storage capabilities. Nutanix storage has been much more advanced (and arguably still is), compared to VMware, providing deduplication, erasure coding, snapshots, and clones from the outset. These capabilities were only introduced into vSphere with the release of vSAN in 2014.

We believe that Nutanix Cloud Platform can match VMware vSphere and the wider VMware ecosystem in every aspect of the platform, making it a complete package for the replacement of a VMware ecosystem. There are several cautions we would highlight for any migration between platforms.

Operational differences. From the basic hypervisor level upwards, vSphere and NCP have fundamental operating differences. For example, ESXi directly supports internal and external storage, whereas Nutanix adds this capability through a guest virtual machine on each cluster node (CVM). Clearly, migrating to a new platform requires an understanding of platform operations, but also extends to aspects such as disaster recovery, cluster rebuilds and upgrades, and monitoring and observability.

Integration. Both platforms offer the capability to automate through CLIs and APIs but will have different syntaxes and structures. Depending on the level of automation in place, some rewriting may be needed. As with any migration to new technology, the number of modifications to existing in-house tools must be gauged on a case-by-case basis.

Performance. There are no easy ways to compare the performance of vSphere to NCP for the same set of hardware. One solution could be to build a test environment in the public cloud and benchmark. Nutanix offers X-Ray for hardware capacity testing, while VMware has VMmark. Both are independent tools designed for their respective platforms rather than generic tools that could be used across any HCI infrastructure.

Commercial Terms

Nutanix provides comprehensive licensing for the components of NCP across three “editions”. These are “Starter”, “Pro”, and “Ultimate”. The Starter Edition supports clusters of up to 12 nodes, with limited storage support and no quality of service.

Nutanix suggests that “Starter” is more focused on a limited set of small-scale workloads, whereas “Pro” and “Ultimate” could be used for public cloud deployments as well as on-premises. The increasing feature set of the more expensive options does map to a more mature set of capabilities.

Note that each option includes AHV, so customers that continue to run on VMware vSphere are effectively paying a “vTax” for the hypervisor and management tools that could be avoided moving to AHV. It’s worth highlighting again that despite this potential saving, only 50% of clusters use AHV today. Selling the benefits of AHV and converting customers over is one obvious opportunity for Nutanix.

Deployment Models

Nutanix Cloud Platform was initially sold through the appliance model, with a range of different configuration options available. From (financial year) 2018, Nutanix moved to a software-only model, packaging hardware from partner suppliers.

Although not an official partner relationship, Nutanix supported Cisco UCS deployments from 2016. In August 2023, Cisco and Nutanix announced a partnership that would see Cisco resell NCP with UCS hardware in place of the discontinued HyperFlex. At the time, we wrote a blog post suggesting that this may be a “try before you buy” process for Cisco. Following the announcement of VMware moving to a subscription model and the termination of partner agreements, the relationship between Cisco and Nutanix could be seen as a prescient and timely move.

As already highlighted, in August 2020, Nutanix announced the availability of NCP in the public cloud, a feature known as Nutanix Cloud Clusters or NC2. The solution runs on bare-metal instances on either AWS or Microsoft Azure, presumably to ensure that support for virtualisation is available.

Features

Nutanix NCP offers a wide range of features that align closely with the VMware ecosystem. Container support (comparable to Tanzu) was announced in 2016, with an in-house solution called Karbon announced in late 2018. This has since been renamed to the Nutanix Kubernetes Engine.

From a platform perspective, Nutanix offers database-as-a-service with Era. As already highlighted, there is also a range of storage services. Nutanix Files (formerly known as Scale-Out File Server and Acropolis File Services) provides file-based storage. Object storage support is delivered by Nutanix Objects (formerly Nutanix Buckets). In a move away from a purely HCI model, Nutanix also offers storage-only nodes alongside the traditional mixed compute and storage architecture design.

Operationally, Nutanix Cloud Manager provides many of the features expected in a software-defined data centre, including automation, self-service, and cost management. Until recently, Nutanix also offered virtual desktop infrastructure, however, this part of the business was sold off to private equity in May 2023.

Migration & Mobility

As already highlighted, Nutanix virtual instances can operate on-premises or within the public cloud. Customers may choose to deploy on AHV, Hyper-V or vSphere, providing a choice of hypervisor. Storage options are less flexible, with support for the HCI model and dedicated storage nodes. Theoretically, NCP could support external shared storage. However, that option is not part of the underlying architectural principles of the platform.

Nutanix provides both professional services and a tool (Nutanix Move) to automate the steps required when converting virtual machines from VMware ESXi to AHV. This process ensures that the correct devices are installed in the VM image and parameters such as MAC address are retained.

The Architect’s View®

With over 24,000 customers, Nutanix is probably the most mature offering in the market as a replacement for the VMware ecosystem. NCP has the advantage of already supporting ESXi as a hypervisor, with well-documented routes to transition away from vSphere installations over to AHV.

However, where the capabilities of shared storage are heavily implemented under a VMware environment, Nutanix doesn’t offer the best choice, as the architectural design of NCP derives from the HCI model. Potential customers could see significant additional expense for in-server storage while shared storage platforms (and their functionality) are made redundant.

We believe that Nutanix will benefit from the confusion and uncertainty around the Broadcom/VMware acquisition, especially in light of the transition to subscription-only and the termination of VMware partner agreements. Nutanix should have opportunities with SMBs and mid-range organisations where resellers have been terminated by Broadcom.

More background on Nutanix can be found in our X-Ray eBook.

X-Ray: Nutanix, Inc.

This Architecting IT report takes a deep dive into Nutanix’s history, products, services, and future outlook. This report is only available for download via paid subscription.

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