Organizations that offer Apple endpoints as work devices must address the specific requirements of macOS in any technology implementation. Desktop virtualization is no exception.
Many organizations have adopted Windows-based VDI and desktop as a service (DaaS) to deploy virtual desktops to end users. The Windows virtual desktop can be based on a ratio of 1-to-many with a server OS, 1-to-1 with a workstation OS or 1-to-many with Windows 10 or 11 multi-user workstation OS. Regardless of the VM's OS, the user experiences a familiar Windows desktop, which they access after successful authentication.
Through DaaS providers, such as Citrix, VMware and Microsoft Azure, users can access Windows-based virtual desktops from any type of Apple device, including an iOS-based iPhone or a macOS-based device such as a MacBook. This type of access is common and has been available for many years. Every end-user device type -- including Google Chromebooks and other Linux-based devices -- can be used, whether in conjunction with a native client or web-based access.
As of April 2022, Apple's macOS holds at least 15% of the global market share of physical desktop OSes. Macs appear in enterprises, such as when users are able to choose their primary device. As an extension of this system's familiarity and functionality, some organizations are interested in subscribing to macOS virtual desktops from a DaaS provider. However, Apple's licensing requirements pose a challenge to this possibility.
The concept of hosting macOS works for two distinct cases: macOS development and macOS DaaS for user access. These two functionalities are not interchangeable.
Developers creating Apple-focused software can use a virtualized macOS desktop to develop and test the software. For example, an enterprise that provides an editing application may wish to have the application run on both Windows and Mac devices. Within the development environment, this could imply physical devices or VMs. Additionally, a virtual macOS desktop frees developers to work from a Windows device, if necessary.
It's easy to create a cloud-based development environment for Windows. Using the cloud minimizes costs and setup work, enhances flexibility and gives developers easy access to the environment. For example, if an error occurs during testing wherein an action programmatically generates an infinite loop, developers can gather forensics to fix the problem and then quickly and easily delete the virtual desktop. They can subsequently correct the issue and test again on a newly deployed Windows-based VM within minutes.
That type of setup was not available for Mac development until recently. While Mac developers can get mini devices for the lab, cloud-based application development and testing is a better option. However, Apple licensing controls what users can and cannot legally do with macOS software.
Licensing for macOS
Apple has stringent licensing requirements for the macOS operating system in terms of hardware and shared services. First, macOS must run on designated Apple hardware, as per the licensing agreement. In addition, service providers or other shared services cannot use macOS because Apple doesn't allow virtualized copies or instances of the Apple software in connection with types of services such as service bureau, time-sharing and terminal sharing.
Apple does permit remote desktop connections, with some limitations. Although users can make multiple connections to one Mac, only one remote session may control the Apple software; the other connections may only observe the connection. This limited connectivity stipulation severely curbs remote access functionality from both a business and technical perspective.
In late 2020, Apple introduced an aspect of licensing wherein service providers could offer hosting services specifically for developers to use. This new section of the licensing agreement, called Leasing for Permitted Developer Services, likewise has strict requirements. However, it does legally allow providers such as AWS to offer macOS instances for development purposes. In addition, several smaller providers, such as MacStadium and MacinCloud, also provide cloud-based macOS instances for developers. Conditions for developer usage include lessee agreement, a minimum lease period of 24 hours and "sole and exclusive use and control." Activities covered include building software from source, automated testing and running the tools to carry out these activities.
The stipulations for Apple use has some ramifications for macOS-based DaaS. Key benefits of DaaS for Windows include centralization and resource sharing, ultimately resulting in lower costs. As macOS licensing requires Apple hardware, disallows service bureau and sharing, and limits connectivity to one controlling session per device, service providers cannot offer macOS DaaS. On-premises deployments of macOS-based virtual desktops are technically possible, but this falls into a gray area of licensing and is costly.
Thus, Apple licensing now permits developers to lease macOS from service providers but prohibits access to DaaS for end users.
DaaS operating system options
Interest in desktop as a service based on macOS certainly exists, but it is not possible from a legal standpoint. Even if it were, the financial investment and costs would likely raise feasibility questions. There's reason to believe Apple will not change its legal requirements in the future. Apple derives significant profit from hardware -- closely coupling its hardware and software is its long-standing business model and key to its success. Apple continues to focus on tying OS functionality to its physical devices. Physical devices running iOS and macOS operating systems continue to proliferate. Supporting these Apple devices for remote access to Windows-based virtual desktops, therefore, shows no signs of slowing down.
An alternative to Windows-based DaaS is Linux VMs. If an organization seeks an OS other than Windows due to Microsoft's licensing costs or other requirements, Linux is an option worth considering. However, end users are far less familiar with Linux, so involving it in a user-facing technology could cause confusion. Further, some traditional software packages such as Office 365 and Microsoft 365 aren't available for direct download onto a Linux machine. While there may be some use cases for Linux VMs, they face challenges from an integration and familiarity perspective for most enterprise users.
Because multi-user Windows 10 and 11 is available only on Microsoft Azure, this functionality is a key feature of Azure Virtual Desktops. Other cloud providers -- including AWS and Google Cloud -- cannot offer multi-user Windows 10 or 11. However, 1-to-1 virtualized Windows 10 and 11 workstations are available. Because Windows OSes are not dependent on native Microsoft hardware, organizations have flexibility and can find ways to cut costs.