Proxmox VE: As mentioned before, Proxmox VE is an open source hypervisor based on GNU/Linux (Debian-based) with a RHEL-based kernel and published under GNU AGPL v3. It differs from the alternative virtualization software as Proxmox provides a central web-based management without further installation. The underlying technologies used are Open Virtuozzo (OpenVZ) and Kernel-based Virtual Machine (KVM), which will be described in Version 1.6. Subscription plans are available for accessing enterprise repository, software updates, and user support.

XenServer: This is a native hypervisor based on GNU/Linux developed by the Xen Project and published under GNU AGPL v2 as open source. For XenServer, a concept of domain is used for all virtual machines, and the most privileged domain (for example, a domain that allows direct access to hardware)— dom0, is used by the hypervisor to manage other domU virtual machines. It supports para-virtualization, which allows a user to run virtualized guests on a CPU without support for virtualization; for example, no Intel VT-x or AMD-V is needed. Amazon Web Service (AWS) is a production example of using XenServer.

VMware ESX/ESXi: This is a bare-metal hypervisor developed by VMware based on a customized kernel called vmkernel, which is a microkernel developed by VMware.

The difference between ESX and ESXi is that ESXi is a free version of ESX with some resource limitations. ESX has a hardware compatibility list that includes many drivers for network cards and SCSI cards. An extra hardware driver can be added to the base installation if needed. On top of the para-virtualization and hardware-assisted virtualization, ESX provides full virtualization as another option.

There are two management tools available: vSphere client and vCenter server. VSphere client is enough for normal administration operation on one ESX while vCenter server allows the user to manage multiple ESXs, including the configuration of advanced features such as high availability and live migration.

Hyper-V server: This is a proprietary virtualization platform produced by Microsoft Corporation running under the Windows platform starting from Windows Server 2008. If you are mainly using a Windows platform as your virtualized guest, it is recommended that you use Hyper-V, especially if you have enabled an Active Directory domain services.

Hyper-V provides better migration options to users; it not only provides live migration, but also provides unlimited guest movements between hosts. The benefit of the features of an Active Directory domain is that Hyper-V provides replica on virtual machines, which allows a user to copy a specific VM from the source's site to the target site asynchronously via a WAN or a secure VPN.