Top Alternatives to VMware vSphere Hypervisor

Xen Project is a hypervisor using a microkernel design, providing services that allow multiple computer operating systems to execute on the same computer hardware concurrently.

Kernel-based Virtual Machine (KVM) is a virtualization infrastructure for the Linux kernel that turns it into a hypervisor. It was merged into the Linux kernel mainline in kernel version 2.6.20.

Proxmox VE is an open-source server virtualization management solution based on KVM and Linux Containers (LXC).

OpenStack is a free and open-source software platform for cloud computing, mostly deployed as infrastructure-as-a-service (IaaS), whereby virtual servers and other resources are made available to customers.

Portable-VirtualBox is a free and open source software tool that lets you run any operating system from a usb stick without separate installation.

Microsoft Hyper-V Server is a stand-alone hyper-visor based virtualization product which includes live migration.

clearVM is a private cloud management solution.

Citrix XenServer is the leading open source virtualization platform.

Bochs (box) is a portable IA-32 and x86-64 IBM PC compatible emulator and debugger mostly written in C++ and distributed as free software under the GNU Lesser General Public License.

oVirt is free, open-source virtualization management platform.

unRAID Server is a partition management software.