ConMan FAQ
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Q: I'm running ConMan on a large cluster and it crashes every time at startup.
How do I configure it to handle more than 1024 consoles?
A: ConMan versions < 0.1.9 are based on select() and are thereby limited by
the number of file descriptors. A file descriptor is needed for each
console, and another is needed for each log file. If you are logging each
console, these versions will be unable to open more than ~510 consoles.
Under Linux, versions >= 0.1.8.3 can sidestep this limitation if they are
compiled against an increased __FD_SETSIZE in the /usr/include headers.
Versions >= 0.1.9 are based on poll() and are no longer constrained by the
number of file descriptors. The daemon sets the current RLIMIT_NOFILE
(ie, the limit on the number of open file descriptors) to the maximum
allowable "hard" limit. On Linux, the system nofile hard limit can be
set in /etc/security/limits.conf.
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Q: I have a cluster where each node's serial port is the console for the next
node. I would like to be able to access all consoles from a single host.
Is there a "serial port forwarding" mechanism to forward the local serial
port to a single conmand daemon?
A: ConMan does not currently support forwarding consoles from one daemon to
another. However, several serial port forwarders exist:
http://freshmeat.net/projects/sredird/
http://freshmeat.net/projects/sercd/
http://freshmeat.net/projects/ser2net/
http://freshmeat.net/projects/msredird/
Chris Worley reports success with ser2net:
> Date: Tue, 02 May 2006 11:12:09 -0700
> From: "Worley, Chris B" <chris.b.worley@intel.com>
> Subject: RE: Conman via distributed serial ports
>
> Ser2net works great.
>
> I setup my "/etc/ser2net.conf" file on each node with:
>
> 2299:telnet:100000:/dev/modem:57600,NONE,1STOPBIT,8DATABITS,-RTSCTS,-XONXOFF
>
> And my /etc/conman.conf as:
>
> CONSOLE name="n1" dev="/dev/ttyUSB0" log="n1"
> CONSOLE name="n2" dev="n1:2299" log="n2"
> CONSOLE name="n3" dev="n2:2299" log="n3"
> CONSOLE name="n4" dev="n3:2299" log="n4"
> CONSOLE name="n5" dev="n4:2299" log="n5"
> CONSOLE name="n6" dev="n5:2299" log="n6"
> CONSOLE name="n7" dev="n6:2299" log="n7"
> CONSOLE name="n8" dev="n7:2299" log="n8"
>
> And run ser2conf on each node from inittab with:
>
> ser2net -n -p 2298
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