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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 E0461C433DF for ; Fri, 29 May 2020 22:21:53 +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 B2EAD207BC for ; Fri, 29 May 2020 22:21:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B2EAD207BC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lists.ewheeler.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35452 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jenNw-0006ag-Rr for qemu-devel@archiver.kernel.org; Fri, 29 May 2020 18:21:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50040) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jemFW-0004sF-1O for qemu-devel@nongnu.org; Fri, 29 May 2020 17:09:06 -0400 Received: from mx.ewheeler.net ([173.205.220.69]:36935 helo=mail.ewheeler.net) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jemFU-0007Tq-Lg for qemu-devel@nongnu.org; Fri, 29 May 2020 17:09:05 -0400 Received: from localhost (localhost [127.0.0.1]) by mail.ewheeler.net (Postfix) with ESMTP id E9CB5A0415; Fri, 29 May 2020 21:08:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at ewheeler.net Received: from mail.ewheeler.net ([127.0.0.1]) by localhost (mail.ewheeler.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id dzMYA0b7eKmB; Fri, 29 May 2020 21:08:35 +0000 (UTC) Received: from mx.ewheeler.net (mx.ewheeler.net [173.205.220.69]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.ewheeler.net (Postfix) with ESMTPSA id 85FA5A0633; Fri, 29 May 2020 21:08:30 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ewheeler.net 85FA5A0633 Date: Fri, 29 May 2020 21:08:29 +0000 (UTC) From: Eric Wheeler X-X-Sender: lists@mail.ewheeler.net To: "Richard W.M. Jones" Subject: Re: [Libguestfs] Provide NBD via Browser over Websockets In-Reply-To: <20200529141315.GU3888@redhat.com> Message-ID: References: <20200528090443.GN7304@redhat.com> <20200529093744.GS3888@redhat.com> <13571029-5bf4-2dfa-6879-0ad2642afb3f@redhat.com> <20200529135042.GJ2755532@redhat.com> <20200529141315.GU3888@redhat.com> User-Agent: Alpine 2.11 (LRH 23 2013-08-11) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="1514185278-310523577-1590786510=:10871" Received-SPF: none client-ip=173.205.220.69; envelope-from=nbd@lists.ewheeler.net; helo=mail.ewheeler.net X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/29 17:09:02 X-ACL-Warn: Detected OS = Linux 3.1-3.10 X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-Mailman-Approved-At: Fri, 29 May 2020 18:20:08 -0400 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: =?ISO-8859-15?Q?Daniel_P=2E_Berrang=E9?= , QEMU , nbd@other.debian.org, Nir Soffer , libguestfs Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --1514185278-310523577-1590786510=:10871 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT On Fri, 29 May 2020, Richard W.M. Jones wrote: > On Fri, May 29, 2020 at 08:58:06AM -0500, Eric Blake wrote: > > On 5/29/20 8:50 AM, Daniel P. Berrangé wrote: > > > > >>>(2) You need to persuade qemu's NBD client to read from a WebSocket. > > >>>I didn't really know anything about WebSockets until today but it > > >>>seems as if they are a full-duplex protocol layered on top of HTTP [a]. > > >>>Is there a WebSocket proxy that turns WS into plain TCP (a bit like > > >>>stunnel)? Google suggests [b]. > > >>> > > >>>[a] https://en.wikipedia.org/wiki/WebSocket#Protocol_handshake > > >>>[b] https://github.com/novnc/websockify > > >> > > >>qemu already knows how to connect as a client to websockets; Dan Berrange > > >>knows more about that setup. I suspect it would not be too difficult to > > >>teach the qemu NBD client code to use a WebSocket instead of a Unix or TCP > > >>socket as its data source. > > > > > >Actually the inverse. The QIOChannelWebsocket impl is only the server > > >side of the problem, as used by QEMU's VNC server. We've never implemented > > >the client side. There is nothing especially stopping us doing that - just > > >needs someone motivated with time to work on it. > > > > In the meantime, you may still be able to set up something like: > > > > local machine: > > iso -> NBD server -> Unix socket -> websockify -> WebSocket > > I guess the idea is to have a zero-install solution for the browser. > As I said in the email earlier this is very common for IPMI-type > remote access to blade servers and in my experience is implemented > using a Java applet and a proprietary protocol terminated at the BMC > (which then emulates a virtual CDROM to the server). There are some > HP blade servers on Red Hat's internal Beaker instance where you can > play with this. For qemu we wouldn't need to invent a new protocol > when NBD is available and already implemented (albeit not yet on top > of WebSockets). > > The NBD server must run inside the browser and therefore be either > written from scratch in Javascript, or an existing server > cross-compiled to WASM (if that is possible - I don't really know). Interesting idea about WASM. I'll see if I can build one of the simple nbd servers that are around. Not sure how to link it to the JS file IO, however. -- Eric Wheeler > > remote machine: > > WebSocket -> websockify -> Unix socket -> qemu NBD client > > > > Adding websocket client support into qemu would reduce the length of > > the chain slightly (for less data copying) by getting rid of a > > websockify proxy middleman, but would not necessarily improve > > performance (it's hard to say where the latency bottlenecks will be > > in the chain). > > Rich. > > -- > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones > Read my programming and virtualization blog: http://rwmj.wordpress.com > libguestfs lets you edit virtual machines. Supports shell scripting, > bindings from many languages. http://libguestfs.org > > --1514185278-310523577-1590786510=:10871--