[Spread-users] Spread rollout to lots of machines

[Matt Sergeant]

On Mon, 2 Feb 2004, Steven Dake wrote:

> Matt,
>
> Spread supports 128 nodes max.  I suspect if you deploy all of them in
> one segment, your going to have serious performance problems (ring
> rotation takes alot of time).  According to the maintainers, spread has
> been tested with 50-60 nodes at one time.

That's definitely not the intention. I want one segment per "rack" (we
call them "towers", but it's basically a 19" rack full of servers).

The solution I've come up with is this RPM post install script:

%post
if ! grep -q '# Tower' /etc/spread.conf; then
perl -e '$data = qx(/sbin/ifconfig eth0 | grep "inet addr");
($ip, $bcast) = $data =~ /inet
addr:\s*(\d+\.\d+\.\d+\.\d+)\s+Bcast:\s*(\d+\.\d+\.\d+\.\d+)/i;
($rhs, $tower, $server) = $ip =~ /^(\d+\.\d+)\.(\d+)\.(\d+)$/;
@range = ($server < 128) ? (1..127) : (128..254);
print "# Tower $tower\nSpread_Segment $bcast:4803 {\n";
print "\tserver-$_  $rhs.$tower.$_\n" foreach (@range);
print "}\n\n";' >> /etc/spread.conf
fi

It looks a bit hacky, but I think it'll work just fine.

Is there a performance penalty for including clients that won't ever join
the group?

Matt.