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 1C192C04FFE for ; Thu, 18 Apr 2024 15:44:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rxTvJ-0005wU-BB; Thu, 18 Apr 2024 11:43:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rxTvH-0005vd-KY for qemu-devel@nongnu.org; Thu, 18 Apr 2024 11:43:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rxTvE-0001BT-Sk for qemu-devel@nongnu.org; Thu, 18 Apr 2024 11:43:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1713455016; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6wF57Na8KP12SJ8r7qxg+aDEgUr4iFUQCEQLjjJSbSs=; b=PC9UeRla0JfxXmHvkP3DtN+9yfDBJ+tKk7XQ6JuphoGUkHh/ty15zHZxgcKQRRw5n/PlNj 5dqsMq7MmaoTsFpBipy9nwZII2CgysQwJTThFEPZ/YUPR+kLkkBQ62x+uUNXm1v4uzQN39 E383uvEmoBVu6oGlbhJ0FIDcbHwIQKk= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-657-Q10jWELUN-OxzJ5qX0pO7Q-1; Thu, 18 Apr 2024 11:43:32 -0400 X-MC-Unique: Q10jWELUN-OxzJ5qX0pO7Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1A16F1C07F3B; Thu, 18 Apr 2024 15:43:31 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C262940357A7; Thu, 18 Apr 2024 15:43:29 +0000 (UTC) Date: Thu, 18 Apr 2024 16:43:27 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Vladimir Sementsov-Ogievskiy Cc: peterx@redhat.com, farosas@suse.de, yc-core@yandex-team.ru, thuth@redhat.com, lvivier@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, pkrempa@redhat.com Subject: Re: [PATCH] migration: do not exit on incoming failure Message-ID: References: <20240417221329.248803-1-vsementsov@yandex-team.ru> <0a1d8984-bc01-41bf-9099-0ef426e848ca@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0a1d8984-bc01-41bf-9099-0ef426e848ca@yandex-team.ru> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.067, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Apr 18, 2024 at 06:40:38PM +0300, Vladimir Sementsov-Ogievskiy wrote: > On 18.04.24 17:37, Daniel P. Berrangé wrote: > > On Thu, Apr 18, 2024 at 01:13:29AM +0300, Vladimir Sementsov-Ogievskiy wrote: > > > We do set MIGRATION_FAILED state, but don't give a chance to > > > orchestrator to query migration state and get the error. > > > > > > Let's report an error through QAPI like we do on outgoing migration. > > > > > > migration-test is updated correspondingly. > > > > > > Signed-off-by: Vladimir Sementsov-Ogievskiy > > > --- > > > > > > Doubt: is exiting on failure a contract? Will this commit break > > > something in Libvirt? Finally, could we just change the logic, or I need > > > and additional migration-parameter for new behavior? > > > > There's a decent risk that this could break apps, whether > > libvirt or something else, especially if the app is just > > launching QEMU with '-incoming URI', rather than using > > '-incoming defer' and then explicitly using QMP to start the > > incoming migration. > > > > I'd say that with '-incoming defer' we should *not* exit on > > migration error, because that arg implies the app explicitly > > wants to be using QMP to control migration. > > > > With the legacy '-incoming URI' it is probably best to keep > > exit on error, as that's comparatively more likely to be used > > in adhoc scenarios where the app/user is ignoring QMP on the > > dst side. > > > > None the less, I think we need to check how libvirt behaves > > with this patch to be sure of no surprises. > > > > Sounds reasonable, thanks! I'll rework it to behave the new > way only with "-incoming defer", and check how libvirt behave with it. If there are problems and/or we want to be super safe wrt backcompat, we could add a new '-incoming managed' as being equivalent to '-incoming defer' but without the implicit exit. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|