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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 067C8C5DF60 for ; Thu, 7 Nov 2019 15:37:41 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id C74CA2178F for ; Thu, 7 Nov 2019 15:37:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hl0LDGXT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C74CA2178F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44464 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSjqu-0004hw-1B for qemu-devel@archiver.kernel.org; Thu, 07 Nov 2019 10:37:40 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:60698) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSjqC-0004Bs-B4 for qemu-devel@nongnu.org; Thu, 07 Nov 2019 10:36:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iSjq9-0004Vj-QT for qemu-devel@nongnu.org; Thu, 07 Nov 2019 10:36:54 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:52065 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iSjq9-0004VR-Jz for qemu-devel@nongnu.org; Thu, 07 Nov 2019 10:36:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573141012; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dK9tP6VheVPY+h5kOHvd2RIPpAhG5X32j11CjHrVhrw=; b=hl0LDGXT5UXBegoPa4u6Azhwe+17xIC1o3U5Ec9NcqsKA2My61jQ/iveShKyvGl6ddozpE 65B/lhDKG16m8sGCPm3KPbVfTTn3qaqSsC2rVst+t60hPY1YA0o762cGRRLP8sYxJFpn4w Q+FP0sDuFB66yGk0cOKRDOe3Q/UEpc4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-313-mBZu14sXMFatvZD82aUiBw-1; Thu, 07 Nov 2019 10:36:50 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0A34B8017DD; Thu, 7 Nov 2019 15:36:50 +0000 (UTC) Received: from [10.3.117.38] (ovpn-117-38.phx2.redhat.com [10.3.117.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E3A6F600F0; Thu, 7 Nov 2019 15:36:48 +0000 (UTC) Subject: Re: [RFC PATCH 06/18] qemu-storage-daemon: Add --nbd-server option To: Kevin Wolf References: <20191017130204.16131-1-kwolf@redhat.com> <20191017130204.16131-7-kwolf@redhat.com> <25f74aa7-0856-a396-fb98-f6b7a337b965@redhat.com> <1bcb5419-183e-fd7b-e53c-fbb315f29703@redhat.com> <20191107083335.GA5007@linux.fritz.box> <20191107152722.GD5007@linux.fritz.box> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <47962dd4-4c2a-257b-0bed-39ad1c143719@redhat.com> Date: Thu, 7 Nov 2019 09:36:48 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191107152722.GD5007@linux.fritz.box> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: mBZu14sXMFatvZD82aUiBw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, pkrempa@redhat.com, armbru@redhat.com, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/7/19 9:27 AM, Kevin Wolf wrote: > Am 07.11.2019 um 14:45 hat Eric Blake geschrieben: >> On 11/7/19 2:33 AM, Kevin Wolf wrote: >>> As a replacement nbd-server-add, I envisioned adding something like a >>> block-export-add, which would work the way that --export already does. >>> It would also come with query-block-exports and block-export-del, and i= t >>> wouldn't contain only NBD devices, but also vhost-user, FUSE, etc. >>> exports. >>> >>> Now I'm wondering if the same would make sense for nbd-server-start. >>> Maybe an API change would even allow us to start multiple NBD servers >>> (e.g. listening on different IP addresses or using different tls-creds)= . >> >> We want that (the ability to run multiple parallel NBD servers) anyway, = to >> allow parallel incremental backups from different points in time to >> different clients. >=20 > Can't you already have multiple exports on a single NBD server for > multiple clients today? Or do you need a different server configuration > for each client? With our current code base, you can only run a single NBD server, with=20 multiple exports, but the TLS creds are shared among all exports. It is=20 indeed technically possible to tweak things where the single server=20 changes _which_ exports are exposed based on _which_ creds were used by=20 the client (but only when TLS is used, and note that qemu-nbd currently=20 refuses to mix TLS and Unix sockets, although I need to post a v2 of a=20 patch I proposed a while back to improve that). But it is easier still=20 to run two separate servers on different ports with two different creds,=20 and where there is no magic on which exports to show merely based on=20 which creds were presented (and this includes a plaintext connection=20 over Unix). Either way, it requires code changes, and most likely for 5.0. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org