Change in vdsm[master]: vm: Automatically add a serial port for a console device

vfeenstr at redhat.com vfeenstr at redhat.com
Tue Sep 2 07:54:31 UTC 2014


Vinzenz Feenstra has posted comments on this change.

Change subject: vm: Automatically add a serial port for a console device
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Patch Set 7:

(3 comments)

http://gerrit.ovirt.org/#/c/25979/7//COMMIT_MSG
Commit Message:

Line 6: 
Line 7: vm: Automatically add a serial port for a console device
Line 8: 
Line 9: Without a serial device the console support does not work for
Line 10: linux systems. We switch from virtio to serial and append a serial
> linux systems -> Linux guests
The problem on windows is that it prevented the shutdown for some reason. Otherwise there was no problem.

When using the serial device for the console, I can actually use the console via virsh. I wasn't able to get it work otherwise. This might be due to the fact that if not using serial console a special kernel commandline might be required (which I did not verify) however using the approach of the patch enables me to do this with the configuration of the guest out of the Box.

Even for FBSD9 I can get the console support working by just enabling the terminal.


When considering http://fedoraproject.org/wiki/Features/VirtioSerial I think the problem is that you rather have to explicitly spawn the console for the virtio/kvm console device. Where as when you use 'serial' instead 'it just works (TM)' ;)
Line 11: port if a console device was defined.
Line 12: 
Line 13: Change-Id: Ifa7b02a7bcaad63017c35c811a194fa42e2b694f


Line 7: vm: Automatically add a serial port for a console device
Line 8: 
Line 9: Without a serial device the console support does not work for
Line 10: linux systems. We switch from virtio to serial and append a serial
Line 11: port if a console device was defined.
> defined -> requirested.
Actually the code implements it as 'when it was defined' not 'when it was requested'.
In the sense of 'defined in the generated xml'
Line 12: 
Line 13: Change-Id: Ifa7b02a7bcaad63017c35c811a194fa42e2b694f


Line 8: 
Line 9: Without a serial device the console support does not work for
Line 10: linux systems. We switch from virtio to serial and append a serial
Line 11: port if a console device was defined.
Line 12: 
> Have you considered possible issues for guest OS that sees a new implementa
I haven't noticed any issues with that. This patch only applies to VMs that have the console device enabled already. 

The advantage of using a serial device is that it won't require virtio support for the console on the guest side.
e.g. using this patch I can enable the serial console on a FreeBSD os and it works, where as without this it doesn't.

I don't understand your comment in regards to oVirt users and console throughput. I think that this is a feature which is quite useful to recover from broken network settings on a guest os or anything without having to reboot the entire VM.
Line 13: Change-Id: Ifa7b02a7bcaad63017c35c811a194fa42e2b694f


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ifa7b02a7bcaad63017c35c811a194fa42e2b694f
Gerrit-PatchSet: 7
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Vinzenz Feenstra <vfeenstr at redhat.com>
Gerrit-Reviewer: Antoni Segura Puimedon <asegurap at redhat.com>
Gerrit-Reviewer: Dan Kenigsberg <danken at redhat.com>
Gerrit-Reviewer: Federico Simoncelli <fsimonce at redhat.com>
Gerrit-Reviewer: Francesco Romani <fromani at redhat.com>
Gerrit-Reviewer: Michal Skrivanek <michal.skrivanek at redhat.com>
Gerrit-Reviewer: Vinzenz Feenstra <vfeenstr at redhat.com>
Gerrit-Reviewer: automation at ovirt.org
Gerrit-Reviewer: oVirt Jenkins CI Server
Gerrit-HasComments: Yes


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