What are some alternatives?
When comparing OpenNebula and Proxmox Virtual Environment, you can also consider the following products
OpenStack - OpenStack software controls large pools of compute, storage, and networking resources throughout a datacenter, managed through a dashboard or via the OpenStack API.
oVirt - oVirt is a virtualization management application.
VMmanager - VMmanager is a QEMU/KVM server virtualization management software, which presents perfect tools for creating virtual machines, providing VPS services, and building cloud infrastructure.
Virtualizor - Virtualizor is a powerful web based VPS Control Panel.
Scalr - Scalr is cloud management software for public & private infrastructure
vSphere Hypervisor - Get a free vSphere Hypervisor by VMware to consolidate your applications and virtualize your servers. Learn how to optimize your server’s performance