[libvirt] specifying -serial telnet: in XML

Daniel P. Berrange berrange at redhat.com
Thu Apr 2 18:51:05 UTC 2009

On Wed, Apr 01, 2009 at 10:13:53PM -0700, Sukadev Bhattiprolu wrote:
> I run qemu (version 0.9.1 kvm-84) with -serial option as follows:
> 	- serial telnet::2445,server
> so I can telnet to 2445 and have a serial console.
> I tried specifying this to libvirt (version 0.6.0) using the following stanza:
>     <serial type='tcp'>
>       <source mode="bind" host="" service="2445"/>
>       <protocol type="telnet"/>
>       <target port="1"/>
>     </serial>
> I checked /var/log/libvirt/qemu/<guest>.log  and found that libvirt
> added 'nowait' to the serial option:
> 	-serial telnet:,server,nowait
> which is fine (I think).
> But when I start my guest, and "telnet 2445" I don't get any
> output even though the guest boots up fine. After the guest boots
> 	$ echo foo > /dev/ttyS0
> in the guest shows the 'foo' in the telnet window. But I don't get the
> boot/shutdown messages.
> I also have the vnc option in the xml,
> 	  <graphics type='vnc' port='5902' autoport='no' listen=''/>
> so if I open vncviewer, I can see the boot messages. The problem with this
> though is if the kernel fails to boot for some reason, the vncviewer exits
> and I can't find the reason the boot failed.
> My kernel boot command line has 'console=ttyS0' option.  Is there anything
> else I need to ensure 'telnet port' displays the messages ? 

That setting should be what's required to make serial console work. Are
you sure you've got it set in the correct place of grub.conf for the 
guest OS ?  I have my guests configured using:

   "console=ttyS0 console=tty"

whch makes messages go to the serial port and graphical console

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