2552752f0b
The ordering of lock manager locks in the libxl driver has a flaw that was uncovered by a migration error path. In the perform phase of migration, the source host calls virDomainLockProcessPause to release the lock before sending the VM to the destination host. If the send fails an attempt is made to reacquire the lock with virDomainLockProcessResume, but that too can fail if the destination host has not finished cleaning up the failed VM and releasing the lock it acquired when starting to receive the VM. This change delays calling virDomainLockProcessResume in libxlDomainStart until the VM is successfully created, but before it is unpaused. A similar approach is used by the qemu driver, avoiding the need to release the lock if VM creation fails. In the migration perform phase, releasing the lock with virDomainLockProcessPause is delayed until the VM is successfully sent to the destination, which avoids reacquiring the lock if the send fails. Signed-off-by: Jim Fehlig <jfehlig@suse.com> Reviewed-by: Cole Robinson <crobinso@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: