Most customers with VDI deployments are running Horizon View, Citrix XenDesktop and XenApp; or other smaller market players such as Dell vWorkspace and Ericom. Few early adopters are also exploring Microsoft VDI with Hyper-V and SCVMM; which has proven to be a stable platform scaling to approximately 1500 virtual desktops.
However, I see an increasing request for a Nutanix KVM supported VDI solution. Customers want to run VDI on Nutanix 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 big factors in VDI adoption leading to many ROI discussions.
I started looking at VDI alternatives for the KVM world and was able to find solutions that could fit the bill for some organizations. Most commercial VDI solutions that are able to broker connections to standalone machines, virtual or physical, are also capable to work with desktops hosted on KVM hypervisor. However, for the purpose of this article I am focusing on solutions that will provide zero dollar cost (except for Microsoft Windows OS).
- 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 hey 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 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 integrate 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 successfully publish Linux applications and Windows applications and desktop.
Pros: Free solution to deliver 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. Looks like Ulteo has been recently acquired and support may be available soon.
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 configurability, 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 simplistic approach. Offers connection load balance for non-persistent desktops. Windows Remote FX is now a good enough protocol for the large majority of use cases. The solution does not require manual DNS management.
Cons: If desktop management such as recompose and refresh is important 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 three examples above when Windows is used as 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 additional advantages, but for companies looking for a cost-effective alternative running on Nutanix KVM hypervisor you should look at one of these options. Also, please note that other solutions such as Leostream will support KVM using Red Hat Enterprise Virtualization (RHEV). In saying that, Nutanix is actively working with partners to make advanced VDI management on Nutanix KVM a reality and you should hear more on this soon.
If you using another method to deliver VDI that I have not shared here, please let me know.
This article was first published by Andre Leibovici (@andreleibovici) at myvirtualcloud.net.