QEMU Console

Hi,

I have several qemu guests running OpenSuse 12.2.

I’ve working serial console for some guests and in others console is not working.

There is no difference in the configs.

I saw one difference in dmesg logs,

For the guests for which console is working has “Console: color *CGA 80x25”

For the guests for which console is not working has “Console: color VGA+ 80x25”

Any idea on how to fix and get the serial console?


Bharathiraja

You need to

  1. Display the exact commands you use to launch your QEMU instances, so it can be understood what method and version of QEMU you are running… eg qemu-kvm, qemu-system, libvirt(which I highly doubt from your description but is possible)

  2. If you’re using a qemu config file. And, if you aren’t this is one way to make your Guests consistent and manage the many variables in a sane way. Otherwise, you may need to explicitly declare variables in the command. When you say “there is no difference in the configs” it can also mean your configs should be more explicit (actually declare the variable).

  3. If you’re using any kind of virtualization manager.

TSU

I use libvirt to start the guest instances. For ex,

virsh start --console slipmap

Domain slipmap started
Connected to domain slipmap
Escape character is ^]

Yes. I use qemu xml config file and there’s no difference between the ones that are working and not working. One difference is the vtconsole driver is CGA for the working ones and VGA for others.

Let me know if you need any other info.

Something new just happened with qemu running on my machine(you might notice a thread I just opened).
So, it’s too early to know if it might be related to what you’re experiencing but until I can resolve on my machine it’s problematic if I can replicate your problem.

Just out of curiousity, what Desktop are you running?
The Desktop I’m looking at closely is
KDE 4.10.5 “release 1” with latest updates.

TSU

Have you tried explicitly specifying CGA in the configs where you’re trying to connect using VGA to see if CGA works for them, too?
Wondering if you created these VMs using QEMU, and if you did if the config files really are identical in almost every respect. Could there be an architectural difference between each Guest? In particular, I’d be curious what the emulated display driver might be for each Guest.

Also,
Are these virtual consoles or real, physical consoles, eg are you simply connecting from the Host Desktop to a Guest console or are you connecting from a text only console over a “real” serial wire, eg terminal connected to your Host by serial cable?

And, curious why you may be launching a generic console instead of a graphical console like virt-viewer.

TSU

Thanks for your help.

Problem is with boot order. CDROM boots into graphical console by default so it’s getting stuck there without printing anything. I changed the boot order which did the trick.

I see how that can be a problem.
Good catch.

TSU