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<div class="moz-cite-prefix">On 04/02/16 12:33, Jonathan E. Brickman
wrote:<br>
</div>
<blockquote cite="mid:56FFF43F.70702@ponderworthy.com" type="cite">
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For those who may be interested, I am seeing the first small
glimmering of what looks like real success, in running multiple
JACK servers on one box for the purpose of distributing DSP load.
I can now reliably have two netjack1 slaves connect to one
netjack1 master, the master running ALSA to hardware, all within
one Linux box under one kernel and one filesystem.<br>
<div class="moz-forward-container"><br>
The way that this works is "containerization" or "sandboxing",
which can give an IP to anything ranging from one running binary
to a large collection. I started the current effort using
Docker containerization, but its standard setups require a lot
of filesystem recreation, each Docker container has an entire
working OS filesystem apart from the kernel; but during the
studies for Docker, I blundered into something else called
firejail, and firejail appears to be just what the doctor
ordered, it seems to do just about everything while using the
existing filesystem, and one can very easily turn off the
features one doesn't need. <br>
<br>
To cut to the chase, after boot and system prep, first one
creates an IP bridge:<br>
<blockquote><tt>sudo brctl addbr br0<br>
sudo ifconfig br0 10.99.99.1/24<br>
</tt></blockquote>
and then starts JACK in the sandboxes:<br>
<blockquote><tt># The master hardware sandbox is named MASTER,
the QJackCTL profile is named MASTER,</tt><tt><br>
</tt><tt># the JACK server is named MASTER.</tt><tt><br>
</tt><tt>nohup firejail --name=MASTER --noprofile --net=br0
--ip=10.99.99.10 \</tt><tt><br>
</tt><tt> /usr/bin/jackd -n MASTER -m -dalsa -r48000 -p256
-n2 -Xseq -D -Chw:NVidia -Phw:NVidia \</tt><tt><br>
</tt><tt> > ~/LOGS/jack-master.log &</tt><tt><br>
</tt><tt><br>
</tt><tt><br>
</tt><tt># The SRO hardware sandbox is named SRO, the QJackCTL
profile for it is named SRO,</tt><tt><br>
</tt><tt># the JACK server is named SRO.</tt><tt><br>
</tt><tt>nohup firejail --name=SRO --noprofile --net=br0
--ip=10.99.99.15 \</tt><tt><br>
</tt><tt> /usr/bin/jackd -n SRO -dnetone \</tt><tt><br>
</tt><tt> > ~/LOGS/jack-sro.log &</tt><tt><br>
</tt><tt><br>
</tt><tt><br>
</tt><tt># Ditto for STRINGS.</tt><tt><br>
</tt><tt>nohup firejail --name=STRINGS --noprofile --net=br0
--ip=10.99.99.20 \</tt><tt><br>
</tt><tt> /usr/bin/jackd -n STRINGS -dnetone \</tt><tt><br>
</tt><tt> > ~/LOGS/jack-strings.log &</tt><br>
</blockquote>
And then connects the JACK servers, by adding jack_netsource
processes into the existing MASTER sandbox:<br>
<blockquote><tt>#!/bin/bash</tt><tt><br>
</tt><tt><br>
</tt><tt># SRO</tt><tt><br>
</tt><tt>nohup firejail --join=MASTER jack_netsource -s MASTER
-H 10.99.99.15 > ~/LOGS/netsource-sro.log &</tt><tt><br>
</tt><tt><br>
</tt><tt># STRINGS</tt><tt><br>
</tt><tt>nohup firejail --join=MASTER jack_netsource -s MASTER
-H 10.99.99.20 > ~/LOGS/netsource-strings.log &</tt><br>
</blockquote>
I have not tested further yet, no clients -- am working on
something closer to production now -- but this is looking very
good, the connections are reported successful, zero xruns, and
on this prototyping box -- 2.6GHz AMD quad, ten-plus years old
-- 0.8% DSP in use on all three JACK servers and very low memory
usage. This is considerably better than I had hoped.<br>
<br>
The sandboxed binaries above, cannot reach outside the one box
as written above, but the excellent and very responsive
developer of Firejail has provided <a moz-do-not-send="true"
href="https://github.com/netblue30/firejail/issues/372">a
method</a>. As a result this could all be done
box-independently -- for instance, if one's "monolith is the
building" (going to have to remember that, Patrick), one could
have all indicated motherboards NFS or SMB to one file server,
and then use a central control GUI machine to run all firejails
on whichever hardware was proven most appropriate, and testing
could become much easier. Along the way I also found 'xpra'
likely to be a very good way to setup such a central control, am
going to test that as a side project.<br>
<br>
I tried using netjack2 first, but ran into mystery behavior,
xruns started piling huge when the second slave connected. So I
went with netjack1, especially because Patrick Shirkey already
proved the above paradigm in multibox mode using netjack1. I am
currently using netjack1 under jackd2, but will change to
netjack under jackd1 if a reason to do so appears.<br>
<br>
I am now working on a working dual-JACK prototype, in a
near-production design, as a next step towards a generally
transportable MultiJACK Patch Management methodology and the
next big build of my Box of No Return :-)<br>
<br>
Cheers, and thanks everyone!!!!<br>
<br>
<div class="moz-signature">-- <br>
<div style="color: #993300; font-size: 0.8em; font-style:
italic;"> Jonathan E. Brickman <a moz-do-not-send="true"
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href="mailto:jeb@ponderworthy.com">jeb@ponderworthy.com</a> (785)233-9977<br>
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</blockquote>
Hey Jonathon,<br>
Definitely interested in this. Thanks for digging in.<br>
Will you be adding this to your Robust Session Management etc..
blog?<br>
<br>
<pre class="moz-signature" cols="72">--
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