[SOLVED] Guest machine on xen boots from cdrom though boot order is specified as hard disk.

severus21 · 09-06-2012, 02:14 AM

I am trying to create a guest machine on xen virtualized environment through libvirt and install rhel on it by booting from cdrom.
I face a issue in booting device. I gave boot order as hd,cdrom. When doing maiden installation, it will find nothing in hard disk and boots from cd.
Once installation is completed and when it boots next time it boots from hard disk. It is the expected behaviour. But it fails to boot from hard disk and again boots from cdrom.

I also tried specifying per boot device option. I specified disk image as boot order 1 and cd image as boot order 2. But when i power on for the first time, it tries to boot from harddisk and finds nothing there and says " No bootable device. Going to power off in 30 seconds". But expected is, it should boot from cd after trying hard disk.

Below is my domain configuration xml file i used to create guest domain.

<domain type='xen'>
<name>vm-2</name>
<memory>1048576</memory>
<vcpu>1</vcpu>
<os>
<type arch='x86_64'>hvm</type>
<loader>/usr/lib/xen/boot/hvmloader</loader>
<boot dev='hd' />
<boot dev='cdrom'/>
</os>
<features>
<acpi/>
<apic/>
<pae/>
</features>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<devices>
<emulator>/usr/lib/xen/bin/qemu-dm</emulator>
<disk type='file' device='disk'>
<source file='/var/lib/libvirt/images/vm-2.img'/>
<target dev='xvda' bus='ide' />

<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
<disk type='file' device='cdrom'>
<source file='/var/lib/libvirt/images/Rhel53.iso'/>
<target dev='hda' bus='ide' />

<readonly/>
<address type='drive' controller='0' bus='1' target='0' unit='0' />
</disk>
<interface type='bridge'>
<source bridge='br0'/>
</interface>
<graphics type='vnc' port='-1' autoport='yes'/>
</devices>
</domain>

I don't know where i am going wrong. So need help in resolving this issue.
Also like to know how these devices are sorted by libvirt and naming of devices in xen virtualization.

Thanks

mago · 09-27-2012, 07:19 PM

I believe that the problem lies on the virtual hardware denomination.
You xvda should be hda and cdrom should be hdc or something else.

Try this:

Code:

<disk type='file' device='disk'>
<source file='/var/lib/libvirt/images/vm-2.img'/>
<target dev='hda' bus='ide' />

<disk type='file' device='cdrom'>
<source file='/var/lib/libvirt/images/Rhel53.iso'/>
<target dev='hdc' bus='ide' />

severus21 · 09-28-2012, 10:43 AM

Thanks..!!! That worked fine. I also came to know that per device boot option doesn't work properly with xen and its a bug with libvirt.

mago · 09-28-2012, 03:06 PM

Remember to tag it as solved