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List:       linux-ha-dev
Subject:    Re: [Linux-ha-dev] Occasionally  heartbeat doesn't start...
From:       Alan Robertson <alanr () unix ! sh>
Date:       2012-03-12 13:43:05
Message-ID: 4F5DFD69.4040305 () unix ! sh
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In this case, it was actually rpcbind that grabbed the port.  AFAIK, 
there is no way to tell it to use or not use a particular port - except 
to grab it first.  That's what portreserve does.  If it is run first, 
and given the right config files, it _will_ keep anyone else from using 
that port.

It makes sense to put port 694 in /etc/portreserve/heartbeat as part of 
our package and include that invocation.

If someone chooses a different port they can always edit that file.

Redhat provides portreserve and starts it by default before rpcbind.

If other distros don't provide it or use it - no harm comes from 
installing the file and attempting to run portrelease.

But for those that provide it, it is a help.



On 03/12/2012 05:43 AM, Lars Ellenberg wrote:
> On Fri, Mar 09, 2012 at 11:52:56AM -0700, Alan Robertson wrote:
> > Hi,
> > 
> > I've been investigating an HA configuration for a customer.  One
> > time in testing heartbeat didn't start, because rpcbind had stolen
> > its reserved port.  Restarting rpcbind made it choose a different
> > random port.  This is definitely an interesting problem - even if it
> > doesn't happen very often.
> > 
> > The best solution to this, AFAIK is to make a file
> > /etc/portreserve/heartbeat with this one line in it:
> > 694/udp
> > 
> > and then add portrelease heartbeat to the init script.
> "rpcbind" used to be "portmap".
> 
> You would need the portreserve daemon available, installed,
> and started at the right time during your boot sequence.
> So that's only a hackish workaround.
> 
> On Debian (Ubuntu, other derivatives) you'd simply add a line
> to /etc/bindresvport.blacklist. But that may fail as well,
> there have been reports where this was ignored for some reason.
> So that again is just a workaround.
> 
> If you know exactly what will register with portmap (rpcbind),
> you can tell those services to request fixed ports instead.
> 
> Typically you do, and those are just a few nfs related services.
> So just edit /etc/sysconfig/* or /etc/defaults/*
> to e.g. include -o and -p options for rpc.statd, and similar.
> 
> This really is a fix, as long as you know all services
> that are started before heartbeat, and can tell them
> to use specific ports.
> 


-- 
     Alan Robertson<alanr@unix.sh>  - @OSSAlanR

"Openness is the foundation and preservative of friendship...  Let me claim from you \
at all times your undisguised opinions." - William Wilberforce \
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