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<p>Hi Richard / Neeraj,</p>
<p>Thanks for bringing this up. It's one of the interesting topic
for IBM.</p>
<p>Some of the thoughts here.....<br>
</p>
<p>When we have multiple BMCs as part of a single system, then there
are 3 main parts into it.</p>
<p>1/. Discovering the peer BMCs and role assignment<br>
2/. Monitoring the existence of peer BMCs - heartbeat <br>
3/. In the event of loosing the master, detect so using #2 and
then reassign the role<br>
</p>
<p>Depending on how we want to establish the roles, we could have
Single-Master, Many-slave or Multi-Master, Multi-Slave. etc<br>
</p>
<p>One of the team here is trying to do a POC for Multi BMC
architecture and is still in the very beginning stage. <br>
The team is currently studying/evaluating the available solution -
Corosync / Heartbeat / Pacemaker".<br>
Corosync works nice with the clusters, but we need to see if we
can trim it down for BMC.<br>
<br>
If we can not use corosync for some reason, then need to see if we
can use the discovery using PLDM ( probably use the terminus IDs )<br>
and come up with custom rules for assigning Master-Slave roles.<br>
</p>
<p>If we choose to have Single-Master and Many-Slave, we could have
that Single-Master as an entity acting as a Point of Contact for
external request and then could orchestrate with the needed BMCs
internally to get the job done<br>
</p>
<p>I will be happy to know if there are alternatives that suit BMC
kind of an architecture</p>
<p>!! Vishwa !!<br>
</p>
<div class="moz-cite-prefix">On 12/10/19 4:32 AM, Richard Hanley
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAH1kD+YrfgnLGdiTOao4t7kXDw7494MQM7pxOAZCbEP6i4EVcw@mail.gmail.com">
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<div dir="ltr">Hi Neeraj,
<div><br>
</div>
<div>This is an open question that I've been looking into as
well. </div>
<div><br>
</div>
<div>For BMC to BMC communication there are a few options.</div>
<div>
<ol>
<li>If you have network connectivity you can communicate
using Redfish.</li>
<li>If you only have a PCIe connection, you'll have to use
either the inband connection or the side band I2C*. PLDM
and MCTP are protocols that defined to handle this use
case, although I'm not sure if the OpenBMC implementations
have been used in production.</li>
<li>There is always IPMI, which has its own pros/cons.</li>
</ol>
<div>For taking several BMCs and aggregating them into a
single logical interface that is exposed to the outside
world, there are a few things happening on that front. DMTF
has been working on an aggregation protocol for Redfish.
However, it's my understanding that their proposal is more
directed at the client level, as opposed to within a single
"system".</div>
</div>
<div><br>
</div>
<div>I just recently joined the community, but I've been
thinking about how a proxy layer could merge two Redfish
services together. Since Redfish is fairly strongly typed and
has a well defined mechanism for OEM extensions, this should
be pretty generally applicable. I am planning on having a
white paper on the issue sometime after the holidays.</div>
<div><br>
</div>
<div>Another thing to note, recently DMTF released a spec for
running a binary Redfish over PLDM called RDE. That might be
a useful way of tying all these concepts together. </div>
<div><br>
</div>
<div>I'd be curious about your thoughts and use cases here.
Would either PLDM or Redfish fit your use case?</div>
<div><br>
</div>
<div>Regards,</div>
<div>Richard</div>
<div><br>
</div>
<div>*I've heard of some proposals that run a network interface
over PCIe. I don't know enough about PCIe to know if this is
a good idea.</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Dec 9, 2019 at 1:27 PM
Neeraj Ladkani <<a href="mailto:neladk@microsoft.com"
target="_blank" moz-do-not-send="true">neladk@microsoft.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div lang="EN-US">
<div>
<p class="MsoNormal">Are there any standards in managing
heterogeneous systems? For example in a rack if there is
a compute node( with its own BMC) and storage node( with
its own BMC) connected using a PCIe switch. How these
two BMC represented as one system ? are there any
standards for BMC – BMC communication? </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Neeraj</p>
<p class="MsoNormal"> </p>
</div>
</div>
</blockquote>
</div>
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