Presence of the virtio-net-pci option called "failover" indicates support in a qemu binary of a simplistic bonding of a virtio-net device with another PCI device. This feature allows migration of guests that have a network device assigned to a guest with VFIO, by creating a network bond device in the guest consisting of the VFIO-assigned device and a virtio-net-pci device, then temporarily (and automatically) unplugging the VFIO net device prior to migration (and hotplugging an equivalent device on the migration destination). (The feature is called "failover" because the bond device uses the vfio-pci netdev for normal guest networking, but "fails over" to the virtio-net-pci netdev once the vfio-pci device is unplugged for migration.) Full functioning of the feature also requires support in the virtio-net driver in the guest OS (since that is where the bond device resides), but if the "failover" commandline option is present for the virtio-net-pci device in qemu, at least the qemu part of the feature is available, and libvirt can add the proper options to both the virtio-net-pci and vfio-pci device commandlines to indicate qemu should attempt doing the failover during migration. This patch just adds the qemu capabilities flag "virtio-net.failover". Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Libvirt API for virtualization
Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
For some of these hypervisors, it provides a stateful management daemon which runs on the virtualization host allowing access to the API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other languages including Python, Perl, PHP, Go, Java, OCaml, as well as mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the website:
License
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.0 (or later). See the files COPYING.LESSER
and COPYING
for full license terms & conditions.
Installation
Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands, however, we mandate to have the build directory different than the source directory. For example, to build in a manner that is suitable for installing as root, use:
$ mkdir build && cd build
$ ../configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ mkdir build && cd build
$ ../configure --prefix=$HOME/usr
$ make
$ make install
The libvirt code relies on a large number of 3rd party libraries. These will
be detected during execution of the configure
script and a summary printed
which lists any missing (optional) dependencies.
Contributing
The libvirt project welcomes contributions in many ways. For most components the best way to contribute is to send patches to the primary development mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
The libvirt project has two primary mailing lists:
- libvirt-users@redhat.com (for user discussions)
- libvir-list@redhat.com (for development only)
Further details on contacting the project are available on the website: