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Chapter 19. Virtualization

ENA drivers for Amazon Web Services

This update adds support for Amazon Elastic Network Adapter (ENA) drivers to the Red Hat Enterprise Linux 7 kernel. ENA significantly enhances networking efficiency of Red Hat Enterprise Linux 7 guest virtual machines for certain instance types of the Amazon Web Services cloud.

Synthetic Hyper-V FC adapters are supported by the storvsc driver

This update improves the way the storvsc driver handles Fibre Channel (FC) devices on Hyper-V virtualization. Notably, when a new synthetic Fibre Channel (FC) adapter is configured on a Hyper-V hypervisor, a new hostX (for example host1) file is created in the /sys/class/fc_host/ and /sys/class/scsi_host/ directories. This file contains the port_name and host_name entries determined by the Hyper-V FC Adapter world-wide port number (WWPN) and world-wide node number (WWNN). (BZ#1308632, BZ#1425469)

Parent HBA can be defined by a WWNN/WWPN pair

With this release, a parent host bus adapter (HBA) can be identified by a World Wide Node Name (WWNN) and World Wide Port Name (WWPN),in addition to a scsi_host#. When defined by a scsi_host#, if hardware is added to the host machine, the scsi_host# may change after the host machine reboots. By using a WWNN/WWPN pair, the assignment remains unchanged regardless of hardware changes to the host machine. (BZ#1349696)

libvirt rebased to version 3.2.0

The libvirt packages have been upgraded to upstream version 3.2.0, which provides a number of bug fixes and enhancements over the previous version. Notable changes:
  • This update makes it possible to install and uninstall specific libvirt storage sub-drivers, which reduces the installation footprint.
  • You can now configure the /etc/nsswitch.conf file to instruct Name Services Switch (NSS) to automatically resolve names of KVM guests to their network addresses. (BZ#1382640)

KVM now supports MCE

This update adds support for Machine Check Exception (MCE) to the KVM kernel modules, which makes it possible to use the Local MCE (LMCE) feature of Intel Xeon v5 processors in KVM guest virtual machines. LMCE can deliver MCE to a single processor thread instead of broadcasting to all threads, which ensures the machine check does not impact the performance of more vCPUs than needed. As a result, this reduces software load when processing MCE on machines with a large number of processor threads. (BZ#1402102, BZ#1402116)

Added support for rx batching on tun/tap devices

With this release, rx batching for tun/tap devices is now supported. This enables receiving bundled network frames which can improve performance. (BZ#1414627)

libguestfs rebased to version 1.36.3

The libguestfs packages have been upgraded to upstream version 1.36.3, which provides a number of bug fixes and enhancements over the previous version. Notable changes include:
  • This update adds the virt-tail utility, which can be used to follow (tail) log files within a guest, similar to the tail -f command. For details, see the virt-tail(1) man page.
  • The virt-v2v utility supports more operating systems and more input sources. In addition, the conversion of Windows guests has been substantially rewritten and simplified.
  • Multiple options have been added for the virt-customize, virt-builder, and virt-systprep utilities. (BZ#1359086)

Improved virt-v2v installation of QXL drivers

This update reworks the virt-v2v implementation of QXL driver installation in Windows guest virtual machines, which ensures that QXL drivers are installed correctly on these guests. (BZ#1233093, BZ#1255610, BZ#1357427, BZ#1374651)

virt-v2v can export disk images to qcow2 format 1.1

With this update, the virt-v2v utility exports disk images compatible with qcow2 format version 1.1 when using the -o rhev option. In addition, virt-v2v adds the --vdsm-compat=COMPAT option for the vdsm output mode. This option specifies which version of the qcow2 format virt-v2v uses when exporting images with the -o vdsm option. (BZ#1400205)

Additional virt tools can work on LUKS whole-disk encrypted guests

This update adds support for working on LUKS whole-disk encrypted guests using the virt-customize, virt-get-kernel, virt-sparsify, and virt-sysprep tools. As a result, these tools can provide keys or passphrases for opening LUKS whole-disk encrypted guests. (BZ#1362649)

Tab completion for all libguestfs commands

Bash completion scripts have been added for all libguestfs tools. As a result, it is now possible to use Tab completion in bash with every libguestfs command. (BZ#1367738)

Resized disks can be written directly to a remote location

With this update, the virt-resize utility can write its output to a remote location. This may be useful, for example, in directly writing the resized disk image to a Ceph storage volume. The virt-resize output disk can be specified using a URI. Any supported input protocol and format can be used to specify the output. (BZ#1404182)

User namespace is now fully supported

The user namespace feature, previously available as a Technology Preview, is now fully supported. It provides additional security to servers running Linux containers by providing better isolation between the host and the containers. Administrators of a container are no longer able to perform administrative operations on the host, which increases security. (BZ#1138782)

Driver added for devices that connect over a PCI Express bus in guest virtual machine under Hyper-V

In this update, a new driver was added that exposes a root PCI bus when a devices that connects over a PCI Express bus is passed through to a Red Hat Enterprise Linux guest virtual machine running on the Hyper-V hypervisor. The feature is currently supported with Microsoft Windows Server 2016. (BZ#1302147)