Most VDI deployments in enterprises run with VMware Horizon View, or Citrix XenDesktop, or with smaller or up and coming market players such as Parallels, Ericom, and Workspot.

However, I see an increasing request for a KVM supported VDI solution. Customers want to run VDI on KVM, eliminating hypervisor license costs, therefore reducing the total cost per desktop. Furthermore, it’s also possible to remove Microsoft licenses if Linux is used. Cost per desktop has been one of the factors playing against VDI adoption and leading to many ROI discussions.

I started looking at VDI alternatives for KVM and was able to find solutions that could fit the bill for some organizations. Most commercial VDI solutions that broker connections to stand-alone machines, virtual or physical, are also capable of working with desktops hosted on KVM hypervisor. However, for this article, I am focusing on solutions that will provide zero dollar software cost (except for Microsoft Windows OS).

• Ravada VDI Project [Update 4/10/2017]

The engineering team from the Universitat Politècnica de Catalunya. BarcelonaTech created a Linux-based VDI solution for qemu-KVM. In their website the Ravada team specify the features available today and on the roadmap.

The solution is simple to install and operate, and the display protocol of choice is KVM spice. The client must have a spice viewer such as virt-viewer. The source code and binaries are available on GitHub, and they welcome contributors.

Pros: Free brokering and hosting solution for KVM.

Cons: Not tested at scale.

• Open UDS [Update 4/10/2017]

OpenUDS Is an Open Source Source project, initiated by Spanish Company Virtualcable and released Open Source with the help of several Spanish Universities. UDS Enterprise is a multiplatform connection broker to manage and deploy virtual and physical desktops, applications and other Windows & Linux services. It supports XenServer/XCP, KVM, and ESXi hypervisors.

Project website: http://www.openuds.org

The source code and binaries are available on GitHub.

Pros: Free brokering and multi-hypervisor support

Cons: Unkown

• KVM-VDI [Update 01/01/2016]

The team at Vilnius University in Lithuania contacted me about an open-source project they have been working on. The University developed a KVM based VDI solution for their computer classes.

The project uses qemu-KVM virtualization and provides VM based sessions with native soft clients via SPICE or RDP protocols. The broker is also able to provide access to virtual desktops created via a VMware Horizon VDI pool on vSphere.

Nice work by the folks at Vilnius University, and for now anyone can test it on any KVM hypervisor or Acropolis. The source code and binaries are available on GitHub.

Also, read New KVM-VDI Open Source Project.

Pros: Free brokering and hosting solution for KVM.

Cons: Not tested at scale.

• Stand-Alone Windows VMs

Virtual desktops are nothing more than virtual machines running Windows or Linux operating systems. Virtual machines with remote display protocols enabled can be treated and accessed as virtual desktops.

Some Nutanix customers decided to use KVM to host stand-alone virtual machines manually provisioned. They use NetBIOS and DNS resolution to allow users to access their desktops. Therefore each user must know or be pre-configured with the virtual desktop FQDN. For this end, they are using a common naming classification for desktop naming that uses the employee’s ID.

Since they use only Windows 7 desktops, they are using RDP, but Linux desktops could also be used with xRDP as an example.

Pros: Zero brokering and hypervisor cost with a simple approach. Windows Remote FX is now a good enough protocol for the large majority of use cases.

Cons: The solution requires individual desktop and DNS management, therefore easy to scale management. There’s no ability to use advanced remote protocol or VDI capabilities; such as auto refresh and recompose.

• Ulteo

Ulteo Open Virtual Desktop (OVD) is a free application delivery platform that uses Windows Remote Desktop Services to publish desktops and applications. Ulteo offers access to Linux hosted desktop and application sessions. Ulteo integrates and seamlessly deliver sessions as a secure service to clients based on Windows, Linux, MacOS, Android, and IOS. After some fiddling with the installation, I was able to publish Linux applications and Windows applications and desktop successfully.

http://www.ulteo.com

Pros: Free solution to deliver a session based application in Windows or Linux. The solution works decently on a local LAN, but not recommended for remote use cases.

Cons: VDI using individual virtual desktops is not supported. It looks like Ulteo has been recently acquired and support may be available soon.

• Crossroads

Crossroads is an open source load balance and fail over utility for TCP based services. It is a daemon running in user space and features extensive reconfigurability, polling of back ends using ‘wakeup calls,’ detailed status reporting, ‘hooks’ for special actions when backend calls fail, and much more. Crossroads is service-independent: it is usable for HTTP(S), SSH, SMTP, DNS, or RDP connections. More info: http://geekcubo.com/2011/09/connection-broker-cross-roads-load-balancer/. This approach will allow for persistent and non-persistent desktop access, but the VM management, if needed, must be done manually.

Theoretically, most load balancers nowadays have this capability, but according to the article linked above the author introduced some special support to use the load balancer as a desktop broker. I will soon test the solution and write another article with my review.

Pros: Zero brokering and hypervisor cost with a simplistic approach. Offers connection load balance for non-persistent desktops. Windows Remote FX is now a good enough protocol for the vast majority of use cases. The solution does not require manual DNS management.

Cons: If desktop management such as recompose and refresh is necessary for you may want to use a commercial solution, but it’s also possible to automate a desktop refresh every night using SYSPREP, snapshots, and scripts.

In the examples above when Windows is used as the operating system, it is possible to have Active Directory integration and authentication, printing (albeit not universal), USB sharing and a good enough remote experience. Microsoft has made its remote desktop client available for many platforms, including iOS, Mac, and Android.

Commercial products offer many advantages, but for companies looking for a cost-effective alternative running on KVM should consider one of these options. Please note that other solutions such as Leostream will support KVM using Red Hat Enterprise Virtualization (RHEV).

If you are using another method, not listed here, to deliver VDI, please let me know.

This article was first published by Andre Leibovici (@andreleibovici) at myvirtualcloud.net.