From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32967) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9XEo-0005qg-Uy for qemu-devel@nongnu.org; Thu, 17 Dec 2015 07:00:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a9XEk-0005Tr-94 for qemu-devel@nongnu.org; Thu, 17 Dec 2015 07:00:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57850) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9XEk-0005TZ-4K for qemu-devel@nongnu.org; Thu, 17 Dec 2015 07:00:46 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id D0186BBF70 for ; Thu, 17 Dec 2015 12:00:44 +0000 (UTC) References: <1450353308-2082-1-git-send-email-berrange@redhat.com> From: Paolo Bonzini Message-ID: <5672A3E9.4020900@redhat.com> Date: Thu, 17 Dec 2015 13:00:41 +0100 MIME-Version: 1.0 In-Reply-To: <1450353308-2082-1-git-send-email-berrange@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC] qemu-char: add logfile facility to socket backend List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" , qemu-devel@nongnu.org On 17/12/2015 12:55, Daniel P. Berrange wrote: > Typically a UNIX guest OS will log boot messages to a serial > port in addition to any graphical console. An admin user > may also wish to use the serial port for an interactive > console. A virtualization management system may wish to > collect system boot messages by logging the serial port, > but also wish to allow admins interactive access. > > Currently providing such a feature forces the mgmt app > to either provide 2 separate serial ports, one for > logging boot messages and one for interactive console > login, or to proxy all output via a separate service > that can multiplex the two needs onto one serial port. > While both are valid approaches, they each have their > own downsides. The former causes confusion and extra > setup work for VM admins creating disk images. The latter > places an extra burden to re-implement much of the QEMU > chardev backends logic in libvirt or even higher level > mgmt apps and adds extra hops in the data transfer path. > > A simpler approach that is satisfactory for many use > cases is to allow the QEMU chardev backends to have a > "logfile" property associated with them. > > $QEMU -chardev socket,host=localhost,port=9000,\ > server=on,nowait,id-charserial0,\ > logfile=/var/log/libvirt/qemu/test-serial0.log > -device isa-serial,chardev=charserial0,id=serial0 Why for socket only? It would be very useful for stdio and especially vc. Paolo