libguestfs is a set of tools for accessing and modifying virtual machine (VM) disk images. You can use this for viewing and editing files inside guests, scripting changes to VMs, monitoring disk used/free statistics, P2V, V2V, performing partial backups, cloning VMs, and much more. libguestfs can access nearly any type of filesystem including: all known types of Linux filesystem (ext2/3/4, XFS, btrfs, etc.), any Windows filesystem (VFAT and NTFS), any Mac OS X and BSD filesystems, LVM2 volumes, MBR and GPT disk partitions, raw disks, qcow2, CD and DVD ISO images, SD cards, and dozens more. libguestfs doesn't need root permissions.
Surealived is a effective LVS (Linux Virtual Server) service tester. It is based on epoll and allows you to detect your hosts' state using HTTP, TCP, DNS, exec, and a universal LUA embedded tester. SSL is also supported. Testers are dynamic modules, and you can extend and write your own modules. You can also dynamicaly change the weight or set real states at run-time. Test states are injected into the kernel IPVS table using the ipvssync application. Configuration is highly extensible, so many testing protocols can be implemented easily.
vidma is a utility for manipulating virtual disk images. It can show basic information about the image or resize it. Resizing is done by in-place modification of a file holding the image or by creating modified copy of such file. The only currently supported format is VDI (Virtual Disk Image), mostly used by VirtualBox.
KaOS is a lightweight, multi-purpose embedded Linux platform designed for virtualization and cloud computing applications. KaOS is based on Linux KVM and is a true enterprise grade hypervisor platform. KaOS makes it easy to deploy KVM based virtualization solutions. KaOS is a lightweight platform, less than 10MB in size. The SDK provides everything necessary to rebuild the platform and comes with scripts to assist with building a KaOS-enabled Linux kernel. KaOS has a menu-driven CLI called AppQueue and a management process that replaces init and other functions called kattach.
Proxmox is a Debian-based bundle of OpenVZ, KVM, and a Web based management GUI. It supports high-performance container-based virtualization of Linux workloads, as well as lower performance KVM hardware assisted virtualization. It supports any hardware that the Linux kernel supports, and will permit live migration of running OSIs with shared storage configurations (DRBD, CIFS, NFS, etc.). It comes bundled with many virtual appliance templates (Drupla, Moodle, FreePBX, etc.) and generic OSI appliances (Fedora, Debian, Ubuntu), as well as a faculty for building arbitrary Linux based appliances. It can be used for virtual desktop infrastructure (VDI) and virtual server infrastructure (VSI). It supports almost any x86/x64 OS in a KVM container and any Linux-based OS in OpenVZ.