FWN/Beats/Virtualization

Virtualization

In this section, we cover discussion on the @et-mgmnt-tools-list, @fedora-xen- list, @libvirt-list and @ovirt-devel-list of Fedora virtualization technologies.

Contributing Writer: Dale Bewley

Fedora 10 Virtualization

This section contains a description of the virtualization features in the brand new Fedora 10 release.

New Features

Fedora 10 includes a number of virtualization enhancements over previous releases including new software packages and major new features.

• Unified Kernel Image

The kernel-xen package has been obsoleted by the integration of paravirtualization operations in the upstream kernel.

• Virtualization Storage Management

Advances in libvirt now provide the ability to list, create, and delete storage volumes on remote hosts.

• Remote Installation of Virtual Machines

Improvements in Virtualization Storage Management have enabled the creation of guests on remote host systems.

For complete details, see the release notes[1] and then jump into the quick start guide[2].

[1] http://fedoraproject.org/wiki/Docs/Beats#Virtualization

[2] http://fedoraproject.org/wiki/Virtualization_Quick_Start

Updates to Virtualization Software

Virtualization with Fedora is achieved through the hard work of many projects including kvm, libvirt, virt-manager, xen, and others.

Below is a listing of some of the virtualization software found in Fedora, illustrating the updates since the release of Fedora 9.

Virtualization Software Versions

Software	F9 Release	F10 Release	Release Notes or Changes
kvm	65-1	74-5	http://kvm.qumranet.com/kvmwiki/ChangeLog
libvirt	0.4.2-1	0.4.6-3	http://www.libvirt.org/news.html
python-virtinst	0.300.3-5	0.400.0-4	http://virt-manager.et.redhat.com/download.html
virt-df	n/a	2.1.4-2	http://et.redhat.com/~rjones/virt-df/
virt-manager	0.5.4-3	0.6.0-3	http://virt-manager.et.redhat.com/download.html
virt-mem	n/a	0.2.9-6	http://et.redhat.com/~rjones/virt-mem/faq.html
virt-top	0.4.1.1-1	1.0.3-2	http://et.redhat.com/~rjones/virt-top/ChangeLog.txt
virt-viewer	0.0.3-1	0.0.3-3	http://virt-manager.et.redhat.com/download.html
xen	3.2.0-10	3.3.0-1	http://www.xen.org/download/
xenner	0.29-2	0.46-3	http://cvs.bytesex.org/xenner.html
xenwatch	n/a	0.5.3-1	http://cvs.bytesex.org/xenwatch.html

Enterprise Management Tools List

This section contains the discussion happening on the et-mgmt-tools list

Connecting to VNC Console on Remote System Installs

While executing virt-install on a remote system, Stephan found[1] that the installer created a VNC service listening on 127.0.0.1, and wanted to know how to connect to this service or move it to a public interface on the remote system.

Daniel P. Berrange answered[2] that modifying the vnc_listen parameter in /etc/libvirt/qemu.conf will affect the IP used, but this isn't necessary. The virt-viewer application will automatically tunnel[3][4] VNC connection over SSH.

virt-viewer --connect qemu+ssh://root@remotehost/system centos1

[1] http://www.redhat.com/archives/et-mgmt-tools/2008-November/msg00041.html

[2] http://www.redhat.com/archives/et-mgmt-tools/2008-November/msg00042.html

[3] http://virt-manager.org/page/RemoteSSH

[4] http://libvirt.org/remote.html

Specifying Installation Media URLs

Enzo Medici became[1] frustrated while trying to provision Xen domUs with virt-manager. "What constitutes a valid install media URL?" "How do you get a valid install media URL for a particular Linux distribution?"

Cole Robinson explained[2] "We actually don't have support in the backend for fetching kernels from Ubuntu trees" yet. "This may work at the moment though since it could be detected as a debian tree." Cole then described the installation URLs for some popular distributions.

• For Fedora, it has varied a bit for different releases, but basically whatever ends in {ARCH}/os:

http://download.fedora.redhat.com/pub/fedora/linux/releases/9/Fedora/x86_64/os/

• CentOS is similar, but seems to have ARCH and os reversed:

http://mirrors.cmich.edu/centos/5/os/x86_64/

• Debian/Ubuntu trees are everything up to the install-{ARCH} dir:

http://us.archive.ubuntu.com/ubuntu/dists/etch/main/installer-i386

[1] http://www.redhat.com/archives/et-mgmt-tools/2008-November/msg00044.html

[2] http://www.redhat.com/archives/et-mgmt-tools/2008-November/msg00046.html

Fedora Xen List

This section contains the discussion happening on the fedora-xen list.

Xen No Graphical Console and CentOS

While creating a domU on CentOS 5.2, Jason passed --nographics to virt-install and received the error message: No console available for domain. Investigation /var/log/xen uncovered: Could not initialize SDL - exiting.

Cole Robinson responded[2] that "This is actually a known bug: xen doesn't abide nographics and tries to init SDL. This will almost always fail if run through [CentOS] 5.2 libvirt. This bug will be fixed in [CentOS] 5.3." The --vnc flag may be used as a workaround this crash in the meantime.

[1] http://www.redhat.com/archives/fedora-xen/2008-November/msg00015.html

[2] http://www.redhat.com/archives/fedora-xen/2008-November/msg00016.html

Libvirt List

This section contains the discussion happening on the libvir-list.

User Mode Linux Support

Daniel P. Berrange improved[1] the user mode linux driver[2] (See FWN#148[3]), by improving stability and adding documentation. Network support is not yet available, but the driver is planned for release with libvirt 0.5.0.

[1] http://www.redhat.com/archives/libvir-list/2008-November/msg00239.html

[2] http://libvirt.org/drvuml.html

[3] http://fedoraproject.org/wiki/FWN/Issue148#Experimental_User_Mode_Linux_Driver

Increased Network Throughput with Large MTU

Chris Wright created[1] a proof of concept patch "for setting a large MTU size on a tap[2] device. With this we are able to improve net i/o throughput substantially (~40% improvement on TX and ~130% improvement on RX). This is just RFC because it's hardcoded to an MTU of 9000 for any tap device."

[1] http://www.redhat.com/archives/libvir-list/2008-November/msg00225.html

[2] http://www.mjmwired.net/kernel/Documentation/networking/tuntap.txt

Integration with SolidICE

With a goal of integrating libvirt and SolidICE[1], Shahar Frank posted[2] "an initial version of the operations required for SolidICE and the proposed high level interface." All of the listed operations were storage related.

Daniel P. Berrange provided[3] a very detailed and informative response explaining how to to apply the libvirt API to these operations.

SolidICE is a product of Qumranet, now Red Hat[4]. SolidICE runs virtual KVM desktops in the datacenter for display by thin clients.

[1] http://www.qumranet.com/products-and-solutions

[2] http://www.redhat.com/archives/libvir-list/2008-November/msg00256.html

[3] http://www.redhat.com/archives/libvir-list/2008-November/msg00262.html

[4] http://fedoraproject.org/wiki/FWN/Issue143#Other_Virtualization_News