Libvirt + Xen cannot boot VMs - TAP device issue
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
OpenStack Compute (nova) |
New
|
Undecided
|
Unassigned |
Bug Description
This bug is being faced on Ubuntu 12.04/13.04 and OpenStack Grizzly.
I cannot start a fully virtualized VM using OpenStack, libvirt and XEN no matter what I have tried so far. The image I am trying is this one: https:/
After a clean hardware (hypervisor) boot, when I try to run the first virtual machine on my libvirt/XEN compute node I get the following error:
libvirtError: POST operation failed: xend_post: error from xen daemon: (xend.err 'Device 51952 (tap2) could not be connected. Device not found.')
From the second time and after, trying to run any virtual machine returns this error :
libvirtError: POST operation failed: xend_post: error from xen daemon: (xend.err 'Device /dev/xvdp (51952, tap) is already connected.')
However the second error looks normal because xenstore-ls shows that /dev/xvdp device is still in use from the previous try... xen-hotplug-cleanup script is not running properly?
Trying to debug this further, I created a simple vm and tried to run it using virt-manager.
The configuration is the same one created by nova-compute, except that I removed the network:
<domain type='xen'>
<name>
<uuid>
<memory unit='KiB'
<currentMemory unit='KiB'
<vcpu placement=
<bootloader>
<os>
<type>
<cmdline>
</os>
<clock offset='utc' adjustment=
<on_poweroff>
<on_reboot>
<on_crash>
<devices>
<emulator>
<disk type='file' device='disk'>
<driver name='tap' type='qcow2'/>
<source file='/
<target dev='sda' bus='scsi'/>
</disk>
<console type='pty'>
<target type='xen' port='0'/>
</console>
<input type='mouse' bus='xen'/>
<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0' keymap='en-us'>
<listen type='address' address='0.0.0.0'/>
</graphics>
</devices>
</domain>
Again with this configuration and manually running this VM with Virt-manager, I face the exact same behaviour described above.
Here you can find some pastebin links with the nova configuration files and logs:
http://
http://
http://
http://
http://
There are two errors here.
First one is related with https:/ /bugs.launchpad .net/nova/ +bug/1188517
The second one is that you're using copy on write (i.e. QCOW2) images with Xen+Libvirt, and it does not work since qcow2 is not supported by blktap2.