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Some layered products such as oVirt have requested a way to avoid being blocked by guest agent commands when querying a loaded vm. For example, many guest agent commands are polled periodically to monitor changes, and rather than blocking the calling process, they'd prefer to simply time out when an agent query is taking too long. This patch adds a way for the user to specify a custom agent timeout that is applied to all agent commands. One special case to note here is the 'guest-sync' command. 'guest-sync' is issued internally prior to calling any other command. (For example, when libvirt wants to call 'guest-get-fsinfo', we first call 'guest-sync' and then call 'guest-get-fsinfo'). Previously, the 'guest-sync' command used a 5-second timeout (VIR_DOMAIN_QEMU_AGENT_COMMAND_DEFAULT), whereas the actual command that followed always blocked indefinitely (VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK). As part of this patch, if a custom timeout is specified that is shorter than 5 seconds, this new timeout is also used for 'guest-sync'. If there is no custom timeout or if the custom timeout is longer than 5 seconds, we will continue to use the 5-second timeout. Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com> Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@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: