slkvm is an application to provide some system tools to work with clustering and virtualization. It focuses on depending on as few external tools as possible but to also support as many virtualization technologies as possible. It works in a cluster environment where heartbeat runs virtual machines of nodes that have failed. It builds an "unheaded" cluster to avoid having a clear point of failure. It is able to build a two node cluster with everything redundant. It avoids compiling a new kernel or newer version of applications, so you can benefit from Debian security updates.
Nuxis is an integrated solution for virtualization management. Some of its features are centralized management of nodes/physical machines and virtual machines, management of virtual networks, storage management, ISO management, monitoring and statistics charts, backup/restore of appliance configurations, import from and export to other virtualization systems using the OVF format, access control, support for multiple operating systems on 32-bit and 64-bit architectures, including Linux and Windows, paravirtualized hardware acceleration drivers, live migrate, PXE boot, Web management, storage management with LVM, and more.