[libvirt] libvirt will create two guest with the same name, but with different UUIDs

29 Apr 2009

      Hi,

libvirt allows you to create two guests with same name, but with 
different UUIDs.

This causes some problems in the reporting though. virsh will report 
that a guest is running (when it isn't). This also causes some confusion 
for the dominfo call - virsh will only return info for one of the 
guests.  I've seen similar issues when using the virDomainLookupByName() 
API.

I suspect all the issues are the same bug, but I haven't had a chance to 
  track down where.

Thanks!

# virsh version
Compiled against library: libvir 0.6.3
Using library: libvir 0.6.3
Using API: QEMU 0.6.3
Running hypervisor: QEMU 0.9.1

# virsh list --all
  Id Name                 State
----------------------------------
109 demo2                running
   - domU1                shut off
   - test_domain          shut off

# virsh dumpxml demo2
<domain type='kvm' id='109'>
   <name>demo2</name>
   <uuid>4dea24b3-1d52-d8f3-2516-782e98a23fa0</uuid>
   <memory>131072</memory>
   <currentMemory>131072</currentMemory>
   <vcpu>1</vcpu>
   <os>
     <type arch='i686' machine='pc'>hvm</type>
     <boot dev='hd'/>
   </os>
   <clock offset='utc'/>
   <on_poweroff>restart</on_poweroff>
   <on_reboot>restart</on_reboot>
   <on_crash>restart</on_crash>
   <devices>
     <emulator>/usr/bin/qemu-kvm</emulator>
     <disk type='file' device='disk'>
       <source file='/tmp/default-kvm-dimage'/>
       <target dev='hda' bus='ide'/>
     </disk>
     <interface type='user'>
       <mac address='24:42:53:21:52:45'/>
     </interface>
     <input type='mouse' bus='ps2'/>
     <graphics type='vnc' port='5900' autoport='yes'/>
   </devices>
</domain>

# cat demo2
<domain type='kvm' id='55'>
   <name>demo2</name>
   <uuid>4dea24b3-1d52-d8f3-2516-782e98a23fa3</uuid>
   <memory>131072</memory>
   <currentMemory>131072</currentMemory>
   <vcpu>1</vcpu>
   <os>
     <type arch='i686' machine='pc'>hvm</type>
     <boot dev='hd'/>
   </os>
   <clock offset='utc'/>
   <on_poweroff>restart</on_poweroff>
   <on_reboot>restart</on_reboot>
   <on_crash>restart</on_crash>
   <devices>
     <emulator>/usr/bin/qemu-kvm</emulator>
     <disk type='file' device='disk'>
       <source file='/tmp/default-kvm-dimage'/>
       <target dev='hda' bus='ide'/>
     </disk>
     <interface type='user'>
       <mac address='24:42:53:21:52:45'/>
     </interface>
     <input type='mouse' bus='ps2'/>
     <graphics type='vnc' port='5902' autoport='yes'/>
   </devices>
</domain>

# virsh define demo2
Domain demo2 defined from demo2

# virsh list --all
  Id Name                 State
----------------------------------
109 demo2                running
   - demo2                running
   - domU1                shut off
   - test_domain          shut off

# ps -ef | grep qemu
root     11464     1 96 09:04 ?        00:02:12 /usr/bin/qemu-kvm -S -M 
pc -cpu qemu32 -m 128 -smp 1 -name demo2 -uuid 
4dea24b3-1d52-d8f3-2516-782e98a23fa0 -monitor pty -pidfile 
/var/run/libvirt/qemu//demo2.pid -no-acpi -boot c -drive 
file=/tmp/default-kvm-dimage,if=ide,index=0,boot=on -net 
nic,macaddr=24:42:53:21:52:45,vlan=0 -net user,vlan=0 -serial none 
-parallel none -usb -vnc 127.0.0.1:0
root     11483 27407  0 09:06 pts/1    00:00:00 grep qemu
#

-- 
Kaitlin Rupert
IBM Linux Technology Center
kaitlin@linux.vnet.ibm.com