VDI for free (alternatives)

Recently I’ve started to explore what free options exist for VDI. The main aim is to develop a computer lab-like environment or one that could be used internet cafés for example.

A very important requirment is that these solutions must be capable of running Windows guests. Those capable of running Linux guests only, are not discussed.

This article will be very much work-in-progress for a long time. Later on I’ll also make also test-implementations of some of them and report on the progress here.

This is a list of  VDI software that I’ve found so far:

1. Citrix XenDesktop Express Edition (currently version 5.6): not open-source, free for up to 10 users, runs with Xen, VMware ESXi and Hyper-V hypervisors.

Details can be found at: http://support.citrix.com/article/CTX127575

2. QVD: free without restrictions (commercial paid support available), runs with KDE hypervisors. Does NOT support Windows host machines.

Details can be found at: http://theqvd.com/

3. NX (NoMachine): different versions, mostly paid. The free version allows two users two connect at the same time. This appears to be Linux based, but will have to explore the details of the offering more.

Details can be found at: http://www.nomachine.com/

There is also an open source implementation: http://freenx.berlios.de/

4. Linux Terminal Server Project (LTSP). This is a purely Linux based project. It seems to be a very mature project. It appears to provide even enterprise-grade functionality and documentation discusses very cool things like server-sizing, integration into a Windows based network, which thin clients to use etc. It’s a very holistic approach.

Details can be found at: http://ltsp.sourceforge.net/

Clouds are an extension to the VDI concept, for the purposes of this discussion. They are actually managed virtualization environments with features like live migration (move VM from one host to another without downtime), central management, reporting and rapid deployment of new VMs. While the public thinks that cloud is always open, for my purposes private clouds are more interesting. Also, instead of the flavors SaaS and PaaS, for my discussion I consider only IaaS, i.e. systems that are a collection of managed virtual machines.

Some of the open source cloud management software are:

1. Eucalyptus: This is a very mature project. It is built to be able to cooperate with AWS (using its API) to allow migration of workloads between AWS and the on-premise private cloud. It can have VMs built for the hypervisors of Xen, VMware or KVM. It comes in Enterprise and OpenSource (free) versions. The Open Source one lacks support for VMware. If you wish you can even become certified for Eucalyptus version 3.

Details can be found at: http://www.eucalyptus.com

2. OpenStack: This is another very mature project, but more one that is constantly evolving. It has a huge supporter base of companies involved. Certainly not the easiest to implement, but appears very open. It supports the hypervisors Xen, KVM, QEMU and VMware.

Details can be found at: http://www.openstack.org/

3. CloudStack: CloudStack is open source software written in java that is designed to deploy and manage large networks of virtual machines, as a highly available, scalable cloud computing platform. CloudStack current supports the most popular hypervisors VMware, Oracle VM, KVM, XenServer and Xen Cloud Platform.

Details can be found at: http://www.cloudstack.org/

4. OpenNebula: It can use all the main hypervisors and provides a management tool for it. Very well documented. My only question is if live-migration or at leas using template machines is possible on an ESXi or another free host.

Details can be found at: http://opennebula.org/

5. FOSS-Cloud: Based on KVM, doesn’t have limitations regarding guest OS. Has very much complete VDI capability set. The only pity is that their documentation is far from being complete. They offer paid professional support.

Details can ben found at http://www.foss-cloud.org

6. Open Source Desktop Virtualization Technology (OSDVT): The Open Source Desktop Virtualization Technology aims to provide a complete solution to deliver Virtual Desktops running in a standalone server over KVM to be accessed using the SPICE protocol.

Details can be found at: http://www.ucs.br/projetos/osdvt

7. Chef: This might be to heavy-weight for a small project. It can orchestrate very different kinds of clients, not only for the cloud. It’s actually more like a server-managent tool. Interestingly, it can also orchestrate various client OS’es like Windows 7 or Vista.

Details can be found at: http://wiki.opscode.com/display/chef/Home

8. openQRM: Similar to Chef, but goes much more in depth. You can not only manage VMs, but be as granular as managing certain CMS’es, so strictly speaking this is not an IaaS-only management system. The entities that can be managed are reachable via so-called plug-ins.

Details can be found at: http://www.openqrm-enterprise.com/

9. Zenoss: Similar to openQRM, but what makes this one special is that it’s agent-less. Will need to review it in more details to tell about its plus- and downsides.

Details can be found at: http://community.zenoss.org/

10. Cantivo: Based on KVM and Spice. Currently client is closed source, but it’s being worked on to open source. Not ready for production environments yet.

Details can be found at: http://cantivo.org/

Furthermore I provide some open source or free tools with a specialized area:

Virtual Networking

1. Open vSwitch: Virtual networking appliance used by man virtualization products. Xen, OpenNebula, KVM, ESX etc. Very mature project.

Details can be found at: http://openvswitch.org/

Virtual Machine Backup

1. Veeam Backup and Replication: This very cool tool allows for backing up and restoring not only full VMs but also the files contained in them. It features a free edition also, which includes the core capabilities as well.

Details can be found at: http://www.veeam.com/virtual-machine-backup-solution-free.html

Virtual Machine Monitoring

1. Veeam ONE: Still needs to be explored.

Details can be found at: http://www.veeam.com/virtual-server-management-one-free.html

Network Storage (SAN / NAS)

To be able to easily move clients between various ESXi servers, it’s wise to store the actual machines on the network and separate it from the machine running the ESXi server part.

ESXi supports NFS, iSCSI and Fibre channel.

Below I’m suggesting a few open source solutions for dedicated storage that’s separate from the ESXi server box.

1. OpenFiler:

Details can be found at: http://www.openfiler.com/

2. FreeNAS:

Details can be found at: http://www.freenas.org

3. UnRAID (by LimeTech): The fully free version can host only 3 HDDs, doesn’t provide user-level security, nor Active-Directory Support. The licences to add this functionality are not that terribly high, though (119 USD currently for a single server).

Details can be found at: http://lime-technology.com/home/87-for-system-builders

4. OpenMediaVault: This seems also quite powerful. Based on Debian. Even though it seems Open Source only, there is lot of activity in the forums, upgrades, plug-ins. This is definitely one that I’ll review later on.

Details can be found at: http://www.openmediavault.org/


1. Spice: This appears to be more like a technology (mainly driven by RedHat). It seems to allow redirection of devices (mouse, display and lot more) then a complete solution. I’ll need to read more about this, but it’s quite surely a very important technology if a thin client is what is aimed at.

Details can be found at: http://spice-space.org

This is a list of hypervisors known to me (work-in-progress):

1. OpenVZ

2. Hyper-V

3. VMware

4. Xen

5. KVM


7. LXC

8. VirtualBox

9. UML (User Mode Linux)
A detailed discussion of virtualization options for Linux are at here.

Other stuff (various)

1. SmallNetBuilder: This appears to be a huge portal, with HOWTO’s, price comparison. Will need to review it later, but appears worth mentioning.

Details can be found at: http://www.smallnetbuilder.com/

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  • Denis  On May 3, 2013 at 3:46 pm

    Another free VDI solution for the home lab:


    “After 30 days, you can continue using 2X ApplicationServer XG for three connections on one terminal server or virtual host and 2X ClientManager for two devices with the FREE license key that you will receive via email after registration.”

  • Adrian  On May 10, 2013 at 6:50 am

    Thanks for the resources and description.

    I am currently writing my thesis on the subject and this article has given me some very good insight information

    Thanks again


    • rock  On October 19, 2013 at 6:53 am

      hi adrian,

      could you please brief about ur project…

  • Chris  On July 16, 2013 at 9:59 pm

    Another Hypervisor option is Proxmox(PVE). Bare metal, pretty robust, can handle Windows, Linux, and other guest OS’s. Ability to for HA cluster with multiple physical servers.

    • winsupsite  On July 17, 2013 at 9:23 pm

      Just read a very positive review about it in iX (a German IT monthly periodical 7/2013).
      It mentions it as a worthy competitor to ESXi and Hyper-V, that is totally free (no restrictions, but you can order support contract that is based on the number of CPUs).
      The article mentions that you can easily clone machines or create templates (not possible in the free ESXi 5) or you can create small VMs that are sharing the kernel with the hypervisor.
      Very interesting approach, I just wish I had time to play around with it (currently just joined the “big blue” and I’m very busy learning new products). So probably there won’t be any frequent updates to this blog until at least October 2013. But that’s not 100% sure, because I could post things that are shorter.

  • Beat  On September 4, 2013 at 3:54 pm

    About article 5. FOSS-Cloud

    Nice to read about FOSS-Cloud in your blog. Thanks about that.

    The working link is http://www.foss-cloud.org

    • winsupsite  On September 11, 2013 at 11:38 am

      Thanks for the notice. Changed the address in the article.

  • xen cloud platform  On September 12, 2013 at 5:53 am

    I have got understand a number of perfectly products listed here. Unquestionably amount book-marking to get revisiting. I’m wondering the fact that great deal effort you set to develop any type of impressive informative web-site.

  • peter  On October 8, 2013 at 3:44 pm

    Virtual Private Cloud (VPC) is an on demand configurable pool of shared computing resources allocated within a public cloud environment, only if certain level of segregation between the dissimilar organizations (denoted as users hereafter) using the resources

  • Anibal Avelar  On December 16, 2013 at 9:12 pm

    You could add these projects:



    it’s a NX based project (but not compatible in all).
    100% Open Source

    Virtual Bridges
    A OpenStack based solution with commercial license.


    SUSE Cloud
    Another OpenStack based solution but SUSE is a platinum partner of OpenStack. Made easy the hard comming from OpenStack.


    Good work by the way.

    • winsupsite  On December 17, 2013 at 1:34 pm

      x2go is definitely a nice one, will explore it later when I have a bit more time.

      However as for vbridges and suse-cloud, I’m not sure where to put them at this point.

      At first sight they are not free (actually why would they, but this post is about “VDI for free (alternatives)”. I might consider putting them into my recent post about various cloud providers.

    • winsupsite  On January 18, 2014 at 9:50 pm

      Hm… I’ve done some research and found that the SUSE cloud is not as easy to be assessed as several others. Have a look at my post regarding IaaS pricing. There you’ll find an overview of the major players in this arena. I’ve excluded those that concentrate on Enterprise customers only and/or don’t publish prices available to anyone.


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