Creation of Xen VM fails with Error: Creating domain failed: name=buildbox03

virtual-machinesxen

Since a few hours, my xen VM does not want to be created.

The VM is quite unstable so I need to destroy and create is quite often. This morning I was able to do such a destroy-create cycle. A few hours later, the destroy – create cycle failed with following error:
The error

~: xm create /etc/xen/buildbox03.cfg -c
Using config file "/etc/xen/buildbox03.cfg".
Error: Creating domain failed: name=buildbox03

errorlogs in /var/log/xen/xend.log:

[2013-05-14 14:11:34 3735] DEBUG (XendDomainInfo:84) XendDomainInfo.create(['vm', ['name', 'buildbox03'], ['memory',  '3072'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'], ['on_crash', 'restart'], ['vcpus', 3],                 ['on_xend_start', 'ignore'], ['on_xend_stop', 'ignore'], ['image', ['linux', ['kernel', '/boot/vmlinuz-2.6.34-1-      netlog'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/xvda1 ro']]], ['device', ['vbd', ['uname', 'phy:/dev/       lvmpool/buildbox03-root'], ['dev', 'xvda1'], ['mode', 'w']]], ['device', ['vbd', ['uname', 'phy:/dev/lvmpool/         buildbox03-swap'], ['dev', 'xvda2'], ['mode', 'w']]], ['device', ['vif', ['bridge', 'br0'], ['mac', '00:16:3E:99:7F:  A1']]],   ['device', ['vif', ['bridge', 'br2'], ['mac', '00:16:3E:99:7F:A2']]]])  
[2013-05-14 14:11:34 3735] DEBUG (XendDomainInfo:1618) XendDomainInfo.constructDomain  
[2013-05-14 14:11:34 3735] DEBUG (balloon:132) Balloon: 11813504 KiB free; need 2048; done.  
[2013-05-14 14:11:34 3735] ERROR (XendDomainInfo:440) VM start failed  
Traceback (most recent call last):  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendDomainInfo.py", line 419, in start  
  XendTask.log_progress(0, 30, self._constructDomain)  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendTask.py", line 209, in log_progress  
  retval = func(*args, **kwds)  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendDomainInfo.py", line 1656, in _constructDomain  
  self.info['name_label'])  
  VmError: Creating domain failed: name=buildbox03  
           [2013-05-14 14:11:34 3735] DEBUG (XendDomainInfo:1897) XendDomainInfo.destroy: domid=None  
               [2013-05-14 14:11:34 3735] ERROR (XendDomainInfo:89) Domain construction failed  
                 Traceback (most recent call last):  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendDomainInfo.py", line 87, in create  
  vm.start()  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendDomainInfo.py", line 419, in start  
  XendTask.log_progress(0, 30, self._constructDomain)  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendTask.py", line 209, in log_progress  
  retval = func(*args, **kwds)  
  File "/usr/lib/xen-3.2-1/bin/../lib/python/xen/xend/XendDomainInfo.py", line 1656, in _constructDomain  
  self.info['name_label'])  
  VmError: Creating domain failed: name=buildbox03  
           [2013-05-14 14:11:34 3735] DEBUG (XendDomainInfo:1897) XendDomainInfo.destroy: domid=None  

buildbox03 config in /etc/xen/buildbox03.cfg:

kernel      = '/boot/vmlinuz-2.6.34-1'  
memory      = '3072'  
vcpus       = 3  
root        = '/dev/xvda1 ro'  
disk        = [  
                  'phy:/dev/lvmpool/buildbox03-root,xvda1,w',  
                  'phy:/dev/lvmpool/buildbox03-swap,xvda2,w',  
              ]  
name        = 'buildbox03'  
dhcp        = 'dhcp'  
vif         = [ 'mac=xxxxxx,bridge=br0', 'mac=yyyyyyy,bridge=br2' ]  
on_poweroff = 'destroy'  
on_reboot   = 'restart'  
on_crash    = 'restart'  

Can you guide me to troubleshoot this problem a bit better?

Best Answer

Although we use XEN since 2007 I never did see an error like yours.

Your DomU-configuration looks good to me, so the error must be within the Hypervisor or the interaction with the Hypervisor of the Dom0 (xend or xenstore).

So some general advice:

For Problems with xenstore (typically: "hotplug-scripts not working"):

Do udevtrigger or udevadm trigger and wait for udev to settle (watch /var/log/messages). After that - try again. If it does still not work - udevtrigger again and retry. Further retries are useless, but this procedure covers about 90% of our xen-related problems.

For problems with xend - your problem looks like one of it: Try to reload the xend service: service xend reload. If that fails try to restart ist: service xend restart.

Be careful here - there might be old hanging xend-processes afterwards that you have to kill manually.

xend restart/reload will not help with xenstore-problems (if you look into the init-script, you will see why: restart/reload dont restart/reload it).

I hope this helps in your case. Try it if your error reappears and comment on it...