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It is increasingly likely that some distro is going to change the default "x86" machine type in QEMU from "pc" to "q35". This will certainly break existing applications which write their XML on the assumption that it is using a "pc" machine by default. For example they'll lack a IDE CDROM and get PCIe instead of PCI which changes the topology radically. Libvirt promises to isolate applications from hypervisor changes that may cause incompatibilities, so we must ensure that we always use the "pc" machine type if it is available. Only use QEMU's own reported default machine type if "pc" does not exist. This issue is not x86-only, other arches are liable to change their default machine, while some arches don't report any default at all causing libvirt to pick the first machine in the list. Thus to guarantee stability to applications, declare a preferred default machine for all architectures we currently support with QEMU. Note this change assumes there will always be a "pc" alias as long as a versioned "pc-XXX" machine type exists. If QEMU were to ship a "pc-XXX" machine type but not provide the "pc" alias, it is too hard to decide which to default so. Versioned machine types are supposed to be considered opaque strings, so we can't apply any sensible ordering ourselves and QEMU isn't reporting the list of machines in any sensible ordering itself. Reviewed-by: Andrea Bolognani <abologna@redhat.com> Signed-off-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 2.1 (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. For example, to build in a manner that is suitable for installing as root, use:
$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ ./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: