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7.111. libvirt

Updated libvirt packages that fix several bugs are now available for Red Hat Enterprise Linux 6.
The libvirt library is a C API for managing and interacting with the virtualization capabilities of Linux and other operating systems.

Bug Fixes

Previously, when the default CPU mask was specified while using Non-Uniform Memory Access (NUMA) pinning, virtual CPUs (vCPUs) could not be pinned to physical CPUs that were not contained in the default node mask. With this update, the control groups (cgroups) code correctly attaches only vCPU threads instead of the entire domain group, and using NUMA pinning with the default cpuset subsystem now works as expected.
The interface configuration of any libvirt domain which was of type='network' and referenced an "unmanaged" libvirt network had incorrect XML data for the interface transmitted during a migration, containing the "status" of the interface instead of the name of the network to use ("configuration"). As a consequence, the migration destination tried to set up the domain network interface using the status information from the source of the migration, and the migration thus failed. With this update, libvirt sends the configuration data for each device during migration rather than the status data, and the migration of a domain using interfaces of type='network' now succeeds.
In Red Hat Enterprise Linux 6.6, support was added for libvirt to report whether QEMU is capable of creating snapshots. However, libvirt did not probe for the snapshot capability properly. As a consequence, the snapshot capability of KVM Guest Image in VDSM was reported as unavailable even when it was available, and creating a disk snapshot in some cases failed. With this update, libvirt no longer reports QEMU snapshot capability, and therefore does not cause the described problem.
Previously, using the "virsh pool-refresh" command, or restarting or refreshing the libvirtd service after renaming a virtual storage volume in some cases caused the "virsh vol-list" to display an incorrect name for the renamed storage volume. This update adds a check for the resulting name, which returns an error if the storage volume name is incorrect.
Prior to this update, when using the "virsh save" command to save a domain to an NFS client with the "root squash" access rights reduction while running the libvirtd service with a non-default owner:group configuration, saving the NFS client failed with a "Transport endpoint is not connected" error message. This update ensures that the chmod operation during the saving process correctly specifies the non-default owner:group configuration, and using "virsh save" in the described scenario works as expected.
A virtual function (VF) could not be used in the macvtap-passthrough network if it was previously used in the hostdev network. With this update, libvirt ensures that the VF's MAC address is properly adjusted for the macvtap-passthrough network, which allows the VF to be used properly in the described scenario.
Users of libvirt are advised to upgrade to these updated packages, which fix these bugs. After installing the updated packages, libvirtd will be restarted automatically.