[Libvir] problems using libvirt to mange "defined" domains.

[Evan Bigall]

I'm having a problem using libvirt to manage "defined" domains (ie:
domains for which it has XML, but are not running.)

I have tried several debugging scenarios, but the simplest one is this. 
In a libvirt C program I define the following XML:

char domxml[]="<domain type='xen' id='99'>"
  "<name>rhel5vm</name>"
  "<uuid>f948d7f4f36c4bfae8053bca535183b3</uuid>"
  "<os>"
    "<type>linux</type>"
    "<kernel>/var/lib/xen/boot/rhel5vm/vmlinuz-2.6.18-8.el5xen</kernel>"
   
"<initrd>/var/lib/xen/boot/rhel5vm/initrd-2.6.18-8.el5xen.img</initrd>"
    "<root>/dev/xvda1</root>"
  "</os>"
  "<memory>512000</memory>"
  "<vcpu>1</vcpu>"
  "<on_poweroff>destroy</on_poweroff>"
  "<on_reboot>restart</on_reboot>"
  "<on_crash>restart</on_crash>"
  "<devices>"
    "<interface type='bridge'>"
      "<source bridge='xenbr0'/>"
      "<mac address='00:16:3e:09:ef:b0'/>"
      "<script path='vif-bridge'/>"
    "</interface>"
    "<disk type='block' device='disk'>"
      "<driver name='phy'/>"
      "<source dev='/dev/sda3'/>"
      "<target dev='xvda'/>"
    "</disk>"
    "<console tty='/dev/pts/2'/>"
  "</devices>"
"</domain>";

(I've played with several values for the domain id).

What I find is that when I use virDomainDefineXML() to define the domain,
for some reason it drops, the "root" element from the "os" specification. 
Because of this the domain then crashes when I try to start it.

I've also tried, using virsh to create the domain from an XML file,
capture the XML with virDomainGetXMLDesc(), pause the C program, and then
try to redefine the domain with the domain with the exact XML
virDomainGetXMLDesc() gave me (after destroying the original of course),
and I get the same behavior, it strips the root element from the OS
specification.

Here is the version information:

[root at rhel5-xen tmp]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5 (Tikanga)
[root at rhel5-xen tmp]# uname -a
Linux rhel5-xen 2.6.18-8.1.8.el5xen #1 SMP Mon Jun 25 17:19:38 EDT 2007
x86_64 x86_64 x86_64 GNU/Linux
[root at rhel5-xen tmp]# virsh version
Compiled against library: libvir 0.3.1
Using library: libvir 0.3.1
Using API: Xen 3.0.1
Running hypervisor: Xen 3.0.0

I am using rhel5 "out of the box" with libvirt upgraded to:
libvirt-0.3.1-1.x86_64.rpm 
libvirt-devel-0.3.1-1.x86_64.rpm 
libvirt-python-0.3.1-1.x86_64.rpm

I tried using libvirt-0.3.2-1, but sample code segv'd in
virConnectClose().

All I'm really trying to do is build a primitive interface to list domains
(both running, and non-running), and start and stop them. I'm open to
suggestions as to whether I have this misconfigured or if there would be a
better version with which to do this.

Thanks,
Evan