From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=dkodihal@linux.vnet.ibm.com; receiver=) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zXn9k0kPWzF0Xj for ; Fri, 2 Feb 2018 17:28:25 +1100 (AEDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w126PNJx112804 for ; Fri, 2 Feb 2018 01:28:23 -0500 Received: from e06smtp12.uk.ibm.com (e06smtp12.uk.ibm.com [195.75.94.108]) by mx0a-001b2d01.pphosted.com with ESMTP id 2fvgm04jjb-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 02 Feb 2018 01:28:22 -0500 Received: from localhost by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 2 Feb 2018 06:28:21 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (9.149.109.195) by e06smtp12.uk.ibm.com (192.168.101.142) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Fri, 2 Feb 2018 06:28:19 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w126SJqp49676412; Fri, 2 Feb 2018 06:28:19 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 18937AE04D; Fri, 2 Feb 2018 06:19:41 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 654A2AE045; Fri, 2 Feb 2018 06:19:40 +0000 (GMT) Received: from Deepaks-MacBook-Pro.local (unknown [9.199.203.113]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 2 Feb 2018 06:19:39 +0000 (GMT) Subject: Re: BMC redundancy To: Andrew Jeffery , openbmc@lists.ozlabs.org References:

<1517532486.2240683.1256645768.23C8305B@webmail.messagingengine.com> From: Deepak Kodihalli Date: Fri, 2 Feb 2018 11:58:17 +0530 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <1517532486.2240683.1256645768.23C8305B@webmail.messagingengine.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18020206-0008-0000-0000-000004C8A856 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18020206-0009-0000-0000-00001E5C4962 Message-Id: <4014865d-271c-0a00-9a22-a2aad663594f@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-02-02_01:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802020072 X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Feb 2018 06:28:26 -0000 On 02/02/18 6:18 am, Andrew Jeffery wrote: > Hi Deepak, > >> So several of the existing OpenBMC apps implement specific D-Bus >> services. What does it take to make remote D-Bus calls to such apps? >> - It doesn't look like the D-Bus spec or libdbus officially has anything >> for D-Bus across computers. There are some good notes at >> https://www.freedesktop.org/wiki/Software/DBusRemote/. > > Applications can cannect to remote dbus servers; the --address option to dbus-daemon allows it to listen on a TCP socket and setting DBUS_SESSION_BUS_ADDRESS will point applications in the right direction. So there are probably two ways we could do this: > > 1. Slave BMCs connect to the master's DBus daemon, and applications namespace their objects appropriately. Multi-BMC aware applications on the master access the namespaced objects as required > 2. Slave BMCs are willfully ignorant of their role, with the master connecting to the slaves' DBus daemons to form a coherent global view of the bus for its multi-BMC aware applications, which access the remote objects as required. > > Given the support DBus has today it might be easier to go for 1 than for 2, if we go down this path at all. I've to look at how/if this is possible in a scenario where any BMC can take on the role of a master, dynamically. > [1] https://dbus.freedesktop.org/doc/dbus-daemon.1.html > >> - There are ways to achieve this via Qt D-Bus, but it would involve some >> amount tweaking with the D-Bus configs. >> - I'm not aware of any open/active project implementing remote D-Bus. > > Here is someone's attempt at making it easier: http://gabriel.sourceforge.net/howto.html though you would struggle to say it's active given the last contribution was 2013-05-14. Yep, did look at this. >> - Thoughts on doing remote D-Bus over WebSockets? > > How do websockets come into the picture? Why do we need the extra complication vs normal sockets? I agree that WebSockets are not the same as plain sockets, there's the additional connection scheme and framing, but the protocol itself doesn't preclude non-browser clients. Why I brought up WebSockets though is for things like sending/receiving (D-Bus) signals asynchronously across BMCs, ping/ping heartbeat messages (surveillance). > Cheers, > > Andrew > Regards, Deepak