[Xymon] Listening on Mulitple IPs

[Chris Ahrens]

Jeremy Laidman <jlaidman at rebel-it.com.au> wrote on 11/13/2011 10:32:21 PM:

> From:
> 
> Jeremy Laidman <jlaidman at rebel-it.com.au>
> 
> To:
> 
> Chris Ahrens <chris.ahrens at macys.com>
> 
> Cc:
> 
> Xymon at xymon.com
> 
> Date:
> 
> 11/13/2011 10:32 PM
> 
> Subject:
> 
> Re: [Xymon] Listening on Mulitple IPs
> 
> On Fri, Nov 4, 2011 at 5:23 AM, Chris Ahrens <chris.ahrens at macys.com> 
wrote:
> > My Xymon server has 3 IP addresses that I want to spread out my 
incoming
> > status messages on.  I did not use the --listen so that xymond would 
come up
> > to use 0.0.0.0:1984 and netstat shows it listening on 0.0.0.0:1984, 
but when
> > I look at the network traffic 99.9% of it is on eth0.
> 
> Is that incoming or outgoing or both?  I believe outgoing traffic will
> route via the "primary" interface regardless of the interface on which
> it arrived, unless you have policy routes in place.  So you might have
> a spread of incoming packets among interfaces, but all outbound
> packets from a single interface.
> 

It was the incoming that wasn't being split up on the different interfaces 
that I was looking for.

> > My client servers are using the dns entry of the Xymon server and dns 
has
> > all 3 IP addresses of the Xymon server associated correctly.
> 
> Is it possible that your resolver is configured to deliver round-robin
> records in fixed order?  Try an "nslookup" a few times and see if the
> order of the 3 IP addresses is changing.  Also look at the TTL of the
> records, to see if it's large, because clients might use the same
> record for a period of time based on the TTL.  Also, try "getent hosts
> <record>" a few times to see if the order is changing, as this will
> indicate what the stub resolver is giving to resolver clients (such as
> the Xymon client).
> 
> DNS round-robin is very poor for load-balancing.  It's not that great
> for fault-tolerance either.  You might try using some kind of
> interface-based traffic sharing, such as bonding.
> 
> Cheers
> Jeremy

The DNS was round-robining just fine to all three IP addresses. The server 
setup is a hot failover and therefore has virtual IP addresses.  The admin 
that built the server had setup all the virutal IPs to eth0 which is why 
all incoming traffic was showing on that interface.  Bonding the 
interfaces would probably be the best idea but I was just configuring 
Xymon and couldn't get the person building the server to bond the 
interfaces.

Thank You,
Christopher Ahrens
Macy's Systems & Technology
chris.ahrens at macys.com
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