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

Enterprise Management Tools List

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

Virt-install Remote Guest Creation

Cole Robinson took[1] a stab at implementing remote guest creation in virt-install. The main unresolved issue was storage. How to detect it and how to allow the user to specify it.

[1] https://www.redhat.com/archives/et-mgmt-tools/2008-July/msg00277.html

Michael DeHaan was interested[2] in teaching koan to install on remote hosts and also focused on the question of storage specification.

[2] https://www.redhat.com/archives/et-mgmt-tools/2008-July/msg00278.html

The discussion of storage specification dovetails well with the concurrent discussion of Storage Pool Discovery on @libvir-list below.

Fedora Xen List

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

kernel-xen is Dead

Mark McLoughlin wrote[1] to say the kernel-xen package is dead. That is to say the kernel package can now support x86 and x86_64 domU guests and kernel-xen will be dropped from Rawhide. Hiding between those lines is the fact that there is currently no Dom0 kernel in Fedora 9 or Rawhide. Without such a Dom0 kernel a domU must be booted via a paravirt_ops kernel or with the KVM-based xenner.

[1] https://www.redhat.com/archives/fedora-xen/2008-July/msg00044.html

The conversation then turned to the matter of migrating away from Xen and support for systems without hardware virtualization. Paul Wouters asked[2] if there was a howto for migration to KVM. It seemed there is not, but all are encouraged to provide one.

[2] https://www.redhat.com/archives/fedora-xen/2008-July/msg00046.html

Alain Williams realized that Fedora 9 has no Dom0 support after installing it. When he asked why Mark McLoughlin pointed[3] out the problems with kernel-xen being based on a much older kernel than kernel creating a time sink, so the decision was made to re-base to the upstream kernel which supports paravirt_ops. This decision was first announced[4] back in Nov 2007 by Daniel Berrange. Mark McLoughlin also stated[3] that Dom0 support at Fedora 10 launch looks unlikely. Fortunately we have more positive news on that front below.

[3] https://www.redhat.com/archives/fedora-xen/2008-July/msg00048.html

[4] https://www.redhat.com/archives/fedora-xen/2007-November/msg00106.html

Dale Bewley bemoaned[5] the fact that he has no budget to upgrade to HVM capable hardware and will have to stick on Fedora 8 until Fedora 10 has Dom0 support. Stephen Smoogen pointed[6] out that RHEL5 and CentOS5 are options for Dom0 on non-HVM hardware. Daniel Berrange expressed[7] some empathy and the desire for such support, but reiterated it isn't viable until Dom0 is ported to pv_ops.

[5] https://www.redhat.com/archives/fedora-xen/2008-July/msg00049.html

[6] https://www.redhat.com/archives/fedora-xen/2008-July/msg00052.html

[7] https://www.redhat.com/archives/fedora-xen/2008-July/msg00053.html

State of Xen in Upstream Linux

Pasi Kärkkäinen thoughtfully forwarded[1] a long detailed xen kernel status message which was sent to the @xen-devel-list by Jeremy Fitzhardinge. Jeremy pointed out that mainline kernel is at 2.6.27-rc1 and his current patch stack is pretty much empty after being merged into linux-2.6.git.

[1] https://www.redhat.com/archives/fedora-xen/2008-July/msg00058.html

Jeremy stated that Fedora 9's kernel-xen package was based on the mainline kernel even though it's been a separate package. Now that kernel-xen has been dropped from rawhide there will be only one kernel package in Fedora 10. Jeremy said his focus in the next kernel development window will be obvious missing dom0 support with the hope it will be merged into 2.6.28. That work will likely take place in a xen.git on Xen.org. Jeremy then provided his long TODO list with a request for help fullfilling it. In addition he asked what's missing.

Paul Wouters followed up[2] on Jeremy's question of "What's missing?" with the answer of a lack of entropy in the guests. Daniel Berrange mentioned Rusty Russell's VirtIO-RNG patch from this thread. Thorsten Leemhuis provided a link to this LWN article on the subject of entropy sources and showed that this patch is in 2.6.26.

[2] https://www.redhat.com/archives/fedora-xen/2008-July/msg00059.html

[3] https://www.redhat.com/archives/fedora-xen/2008-August/msg00000.html

Creating Multiple Xen Bridges

Andy Burns asked[1] for a clean way to utilize the two NICs in a Dom0 server as multiple bridges. Kanwar Sandhu recommended[2] editing xend-config.sxp to utilize a very small custom network-bridge-wrapper script also provided in the post. Another option pointed[3] out on the list was to short-circuit xend-config.sxp and configure all networking by hand in /etc/sysconfig/network-scripts.

[1] https://www.redhat.com/archives/fedora-xen/2008-August/msg00004.html

[2] https://www.redhat.com/archives/fedora-xen/2008-August/msg00005.html

[3] https://www.redhat.com/archives/fedora-xen/2008-August/msg00008.html

Libvirt List

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

PATCH: Storage Pool Discovery

David Lively refered[1] to a post[2] on "Storage Management APIs" by Daniel Berrange when he posted a patch to implement virConnectDiscoverStoragePools. As the API continues to be solidified, this patch implements discovery for only logical and netfs storage pools.

Daniel Berrange pointed[3] to the Storage Management page on libvirt.org as an appropriate place to document the XML used for srcSpec.

[1] https://www.redhat.com/archives/libvir-list/2008-July/msg00502.html

[2] http://www.redhat.com/archives/libvir-list/2008-February/msg00107.html

[3] https://www.redhat.com/archives/libvir-list/2008-August/msg00013.html

PATCH: Fix Setting of Bridge Forward-delay

Christoph Höger described[1] a problem which caused a bridge to not pass traffic for a number of seconds after activation. Just a few minutes later Daniel Berrange posted[2] a fix for a bug which caused libvirt to ignore the forwarding delay when it was set to 0. The workaround in the meantime is to set fd=1.

[1] https://www.redhat.com/archives/libvir-list/2008-August/msg00017.html

[2] https://www.redhat.com/archives/libvir-list/2008-August/msg00020.html

Daniel Veillard plus-oned[3] that patch and expressed that with the last release having been on June 25th, it may be time for a new release. Daniel Berrange mentioned[4] that the Xen & QEMU refactoring needs more testing, and the LXC and OpenVZ drivers need porting to the new XML routines. Richard W.M. Jones wanted[5] to get virsh edit in. The last word[6] was to delay another week.

[3] https://www.redhat.com/archives/libvir-list/2008-August/msg00025.html

[4] https://www.redhat.com/archives/libvir-list/2008-August/msg00030.html

[5] https://www.redhat.com/archives/libvir-list/2008-August/msg00034.html

[6] https://www.redhat.com/archives/libvir-list/2008-August/msg00036.html

oVirt Devel List

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