[fedora-virt] ubuntu 9.10 KVM on fedora 11 question

[Richard W.M. Jones]

On Thu, Nov 05, 2009 at 12:03:01PM -0500, Tom Horsley wrote:
> I have some very weird behavior with my new ubuntu 9.10
> virtual machines running as KVMs under fedora 11.
> 
> I run testbeds on lots of different linuxii in ssh sessions
> to virtual machines, and the ssh session just stops randomly
> when talking to ubuntu 9.10 (no problem with 9.04, or 8.10,
> no problem with various fedora versions or openSUSE versions).

Do the guests have libvirtd running inside them?  libvirtd tends to
create a default network (192.168.122.*) which conflicts with the host
virbr0 network.  This usually breaks networking completely -- I've not
seen is cause hangs on an existing working network, unless ssh is
hanging while something is starting up libvirtd.

https://bugzilla.redhat.com/show_bug.cgi?id=509458

If not that, then these problems are often caused by specific classes
of packets getting through (eg. packets that are too large, have
broken checksums etc).  So as Mark said, a tcpdump is vital to solve
the issue.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
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http://et.redhat.com/~rjones/virt-top