From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E317C43219 for ; Thu, 13 Jan 2022 16:16:11 +0000 (UTC) Received: from localhost ([::1]:38000 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n82ln-0007xr-07 for qemu-devel@archiver.kernel.org; Thu, 13 Jan 2022 11:16:11 -0500 Received: from eggs.gnu.org ([209.51.188.92]:37254) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n82hO-0004yV-Qi for qemu-devel@nongnu.org; Thu, 13 Jan 2022 11:11:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:48848) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n82hN-0006ap-71 for qemu-devel@nongnu.org; Thu, 13 Jan 2022 11:11:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642090293; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=M2Hjsmexf7hY+DSkVVbBArt5yjF2SPD1JIyX6Kvtaxc=; b=YqjzjAnPR5cOmDFIEaIXRTDpd/1hUuX1OQbTa/g0z6YeJHZ8kaLeBnIP6JCs/xC8keVrpU XjLx8SbVlCTcqt19NwfT/FlLec+MWqMOXeQ444G5pDy2iZn3pNJvL7N++hxtgxLqoNhEES SM+6GIQdkVLhK2ZoD/7WJpOgGuwXiA0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-245-y9Dsq9wIOzabx8RQoxlyOw-1; Thu, 13 Jan 2022 11:11:30 -0500 X-MC-Unique: y9Dsq9wIOzabx8RQoxlyOw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0EF768E34CE; Thu, 13 Jan 2022 16:10:51 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-9.ams2.redhat.com [10.36.112.9]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 59D9978AB8; Thu, 13 Jan 2022 16:10:50 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id D977C11380A2; Thu, 13 Jan 2022 17:10:48 +0100 (CET) From: Markus Armbruster To: "Richard W.M. Jones" Subject: Re: Redesign of QEMU startup & initial configuration References: <87lf13cx3x.fsf@dusky.pond.sub.org> <20220104124059.GA1341@redhat.com> Date: Thu, 13 Jan 2022 17:10:48 +0100 In-Reply-To: <20220104124059.GA1341@redhat.com> (Richard W. M. Jones's message of "Tue, 4 Jan 2022 12:40:59 +0000") Message-ID: <87tue762gn.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.594, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , "Daniel P. =?utf-8?Q?Berrang=C3=A9?=" , Paolo Bonzini , Mark Burton , qemu-devel@nongnu.org, Mirela Grujic , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , "Edgar E. Iglesias" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" "Richard W.M. Jones" writes: > Sorry for very delayed reply ... > > On Thu, Dec 02, 2021 at 07:57:38AM +0100, Markus Armbruster wrote: >> 1. QMP only >> >> Management applications need to use QMP for monitoring anyway. They >> may want to use it for initial configuration, too. Libvirt does. >> >> They still need to bootstrap a QMP monitor, and for that, CLI is fine >> as long as it's simple and stable. > > libguestfs actually does not use the QMP monitor but manages to > configure eveything from the command line just fine. I've attached > below a typical example. (Of course we can use libvirt too, but still > for many configurations libvirt causes problems unfortunately). This is just the example I've been looking for: an application that doesn't really need "QMP only". Thanks! >> Human users struggle with inconsistent syntax, insufficiently expressive >> configuration files, and huge command lines. > > One advantage of "huge command lines" is that they document the > configuration of qemu quite well. I know it's only an approximation, > but in many cases it's exactly what we want. It is frequently the > case when troubleshooting that we ask the user "what is the qemu > command line", and they can get that from the libvirt log file or > through "ps". Yes. > So we need to consider this and make sure that everything is changed > so we don't regress. libguestfs will need substantial changes and I think we should try to accomodate how libguestfs wants to use QEMU. > libvirt must dump the full configuration (qinfo or whatever) to the > log file. I believe the entire QMP traffic needs to be logged. CLI + configuration files are all or nothing: if QEMU starts, all, else nothing. When you configure via QMP, any command may fail, and these failures are not fatal. In general, we can also have run-time configuration changes via QMP, such as hot plug. Another reason to log all QMP traffic. > I don't really disagreee with anything else you wrote however. Thanks!