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Revision as of 01:08, 20 October 2008 by Dale (talk | contribs) (→‎Libvirt List: Experimental Driver Thread Safety)

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

Enterprise Management Tools List

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

Starting Guests from a Desktop Icon

Orion Poplawski said[1] "I'd like to provide an icon that would startup the virtual machine and connect to it." Cole Robinson posted[2] a couple of ways to accomplish this.

  • With virt-manager and support for CDROM and USB devices
UUID=`virsh --connect qemu:///system domuuid vm-name`
virsh --connect qemu:///system start $UUID
virt-manager --connect qemu:///system \
             --show-domain-console=$UUID
  • With virt-viewer which won't support CDROM and USB access
UUID=`virsh --connect qemu:///system domuuid vm-name`
virsh --connect qemu:///system start $UUID
virt-viewer --connect qemu:///system $UUID

Each solution requires adequate user permissions to work.

[1] https://www.redhat.com/archives/et-mgmt-tools/2008-October/msg00100.html

[2] https://www.redhat.com/archives/et-mgmt-tools/2008-October/msg00103.html

libvirt Plugins for Performance Monitoring Applications

Guido Günther announced[1] the creation of plugins[2] for net and block I/O monitoring in Munin[3].

Daniel Veillard posted[4] a patch to add this and similar plugins for collectd[5] and Nagios[6] to the libvirt applications page[7].


[1] https://www.redhat.com/archives/et-mgmt-tools/2008-October/msg00118.html

[2] http://munin.projects.linpro.no/

[3] http://honk.sigxcpu.org/projects/libvirt/monitor/

[4] https://www.redhat.com/archives/et-mgmt-tools/2008-October/msg00121.html

[5] http://collectd.org/plugins/libvirt.shtml

[6] http://et.redhat.com/~rjones/nagios-virt/

[7] http://libvirt.org/apps.html"

Fedora Xen List

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

Libvirt List

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

Openvz Bridge Support and Related Patches

Daniel Berrange posted[1] a patch series "derived from Anton Protopopov / Evgeniy Sokolov bridge device patches. It first does some generic refactoring of MAC address handler in all drivers, then adds code to extract OpenVZ[2] version number, then does network config, and finally does filesystem config."

[1] https://www.redhat.com/archives/libvir-list/2008-October/msg00323.html

[2] http://wiki.openvz.org/

Guest Image Locking

Itamar Heim asked[1] "how libvirt envisions image locking. i.e., how do we make sure multiple nodes are not trying to access the same storage volume".

Daniel Berrange said[2] in the domain XML format "the semantics are that every <disk> section added to a guest config is read-write, with an exclusive lock. To allow multiple guests to use the same disk, is intended that you add either <readonly/> or <sharable/> element within the <disk>."

Adding, "we only implement this for the Xen driver, handing off the actuall logic to XenD to perform. That we don't implement this in the QEMU driver is a clear shortcoming that needs addressing. "

The problem on a single host is relatively simple, but more complex among multiple host nodes. Guido Günther has been toying[3] "with the idea of using DLM[4] for libvirt".

[1] https://www.redhat.com/archives/libvir-list/2008-October/msg00334.html

[2] https://www.redhat.com/archives/libvir-list/2008-October/msg00336.html

[3] https://www.redhat.com/archives/libvir-list/2008-October/msg00342.html

[4] http://sources.redhat.com/cluster/dlm/

Exporting the Label on Block Devices

Chris Lalancette described[1] his patch "To support LVM partitioning in oVirt, one of the things we need is the ability to tell what kind of label is currently on a block device. Here, a 'label' is used in the same sense that it is used in parted; namely, it defines which kind of partition table is on the disk, whether it be DOS, LVM2, SUN, BSD, etc." Not the partition type.

[1] https://www.redhat.com/archives/libvir-list/2008-October/msg00341.html

Experimental User Mode Linux Driver

Daniel P. Berrange applied[1] a patch that "implements a driver supporting User Mode Linux[2] guests. User mode linux is a kind of paravirtualized kernel which runs on a plain Linux host. It requires no elevated privileges at all, except for some of the network integration. It is a pretty straightforward thing to invoke, so I figured it would be easy to write a driver to support it. I was right :-)"

[1] https://www.redhat.com/archives/libvir-list/2008-October/msg00355.html

[2] http://user-mode-linux.sourceforge.net/

Experimental Driver Thread Safety

Daniel P. Berrange continued[1] work toward making libvirt thread-safe. The "series of 5 patches implement basic thread safety for the QEMU, LXC and Network drivers. It does not address the OpenVZ or Test driver yet. The Xen driver is totally stateless so does not require changes - though I do need to verify there's no 'static' variables that are used in an unsafe yet in Xen drivers." Daniel's earlier work was referenced[2] in FWN #146.

[1] https://www.redhat.com/archives/libvir-list/2008-October/msg00417.html

[2] http://fedoraproject.org/wiki/FWN/Issue146#libvirtd_Multi-threaded_Support_in_the_Works

oVirt Devel List

This section contains the discussion happening on the ovirt-devel list.

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