98fe739e37
Before the refactoring that properly separated the network driver from the hypervisor driver and forced all interaction to go through public APIs, all network usage counters were zeroed when the network driver was initialized, and the network driver's now-deprecated "semi-private" API networkNotifyActualDevice() was called for every interface of every domain as each hypervisor "reconnected" its domains during a libvirtd restart, and this would refresh the usage count for each network. Post-driver-split, during libvirtd restart/reconnection of the running domains, the function virDomainNetNotifyActualDevice() is called by each hypervisor driver for every interface of every domain restart, and this function has code to re-register interfaces, but it only calls into the network driver to re-register those ports that don't already have a valid portid (ie. one that is not simply all 0), assuming that those with valid portids are already known (and counted) by the network driver. commit 7ab9bdd47 recently modified the network driver so that, in most cases, it properly resyncs each network's connection count during libvirtd (or maybe virtnetworkd) restart by iterating through the network's port list. This doesn't account for the case where a network is destroyed and restarted while there are running domains that have active ports on the network. In that case, the entire port list and connection count for that network is lost, and now even a restart of libvirtd/virtnetworkd/virtqemud, which in the past would resync the connection count, doesn't help (the network driver thinks there are no active ports, while the hypervisor driver knows about all the active ports, but mistakenly believes that the network driver also knows). The solution to this is to not just bypass valid portids during the call to virDomainNetworkNotifyActualDevice(). Instead, we query the network driver about the portid that was preserved in the domain status, and if it is not registered, we register it. (NB: while it would technically be correct to just generate a new portid for these cases, it makes for less churn in portids (and thus may make troubleshooting simpler) if we make the small fix to virDomainNetDefActualToNetworkPort() that preserves existing valid portids rather than unconditionally generating a new one.) Signed-off-by: Laine Stump <laine@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. 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: