From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33631) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XxuvY-0005GQ-F0 for qemu-devel@nongnu.org; Mon, 08 Dec 2014 04:48:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XxuvR-0007AJ-MV for qemu-devel@nongnu.org; Mon, 08 Dec 2014 04:48:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49137) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XxuvR-0007AC-FP for qemu-devel@nongnu.org; Mon, 08 Dec 2014 04:48:17 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sB89mG1H025496 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Mon, 8 Dec 2014 04:48:16 -0500 Received: from redhat.com (vpn1-4-188.ams2.redhat.com [10.36.4.188]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id sB89mDDE021218 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO) for ; Mon, 8 Dec 2014 04:48:15 -0500 Date: Mon, 8 Dec 2014 09:48:12 +0000 From: "Daniel P. Berrange" Message-ID: <20141208094812.GA29159@redhat.com> References: <20141205213518.GD84915@thor.bakeyournoodle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20141205213518.GD84915@thor.bakeyournoodle.com> Subject: Re: [Qemu-devel] Providing a mechanism to reopen() file based chardevs Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org On Sat, Dec 06, 2014 at 08:35:19AM +1100, Tony Breeds wrote: > Hi All, > Openstcak (Nova) has had an issue for a longish time where a running > instance (qemu via libvirt) which has a file based console can fill the disk of > the hypervisor causing all guests to stall. > > I'm looking at ways to fix this. Clearly it can be done in openstack wothout > changing qemu but it seems to be that a better idea would be to teach qemu to > reopen() these files when it recieves a sighup and/or something in the monitor. My long term desired approach to deal with this problem in OpenStack (and other libvirt based mgmt apps) is to have a separate log daemon in libvirt eg a virtlogd daemon. Take QEMU out of the business of writing to files entirely and instead it would always just be a given a pipe FD which is connected to the daemon. This avoidis the need to give QEMU permission to open files at all, which is inline with our general security strategy for host resources QEMU accesses. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|