Re: [lvs-users] 2 Quick Questions

To: " users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] 2 Quick Questions
From: Joseph Mack NA3T <jmack@xxxxxxxx>
Date: Tue, 30 Oct 2007 12:06:47 -0700 (PDT)
On Tue, 30 Oct 2007, Robinson, Eric wrote:

> 1. I've notice that when ldirectord checks to see whether RealServers
> are up, it uses the node's physical IP address as the source. This
> complicates our business partner VPN configs. Is there a way to make it
> use the virtual IP address instead?

yes. my ancient configure script does that (it only sets up 
realservers and not failover directors, so no-one uses it 
anymore). AFAIconcerned, this is the only way to do it, 
since you don't have to get your service to listen on the 
RIP as well.

You ssh from the director to the RIP and run a test on the 
realserver for the service of interest. I use multiscan (see 
sourceforge for this general purpose service tester - it's a 
bit old now, but services haven't changed).

director:# ssh $realserver_name '/usr/local/bin/multiscan -t $vip'

multiscan returns the ports open and you can grep for your 
service. This isn't as stringent a test as requiring the 
service to return a valid string from a query, but it was 
good enough for me. You could substitute mon or your own 
test for the service.

> 2. Is there a hard limit to the number of virtual servers?

a virtual server is a VIP;port. Is that what you're asking?

> Right now I'm running 50-60 of them and the LVS machine is 
> not working especially hard. It's using about 500MB RAM 
> and runs at less than 10% average CPU.

the limit is the amount of memory used for connections, not 
the number of virtual services, it's about 

> Sorry about the following disclaimer. It's appended by the corporate
> mail server...

I have one of those too, but I can get out to my personal 
account from work and look like a normal person.


Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at
Homepage It's GNU/Linux!

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