Re: Service monitoring

Ong,

--- ong cheechye <[email protected]> wrote:
> You mean if I don't have send/expect statement,
> ipvsadm will do the port monitoring somehow. If I
> put
> send="" and expect="", then nanny will monitor the
> port instead. Then what is the difference between
> the
> methods used by ipvsadm and nanny for monitoring the
> service port in the above two cases?

Here's a part of the output from "ps -ef" showing the
three methods Piranha uses to check ports/services. 
The first is the explicit use of a shell script (such
as one that telnets to the port), the second is a
string of chars specified to be sent to the port
(usually http only), and the third is the default if
you do not specify any test method, then IPVSADM is
used by Piranha:

/usr/sbin/nanny -c -h 134.126.12.41 -p 23 -e 
/etc/sysconfig/ha/test_smtp.sh root 

/usr/sbin/nanny -c -h 134.126.12.41 -p 80 -s GET /
HTTP/1.0\r\n\r\n -xroot     

/usr/sbin/nanny -c -h 134.126.12.41 -p 443 -a 15 -I
/sbin/ipvsadm -t 6

You are best off doing a "man ipvsadm" to check out
its options.

 
> It would be useful for me to know as I encounter log
> reported by nanny saying it can't contact the
> realserver though I can ping/telnet RIP from the
> director ? I suspect it has something to do with the
> eth compatibility between director and realserver as
> I
>  somehow avoid the problem if I change the
> combination
> of director and realserver PC. 


I'm not sure what you mean here.  If you mean you
cannot directly ping or telnet the real server from
your PC outside the Virtual Server (piranha cluster)
the that is correct because your real servers have
their default gateways set to the Piranha LVS servers.
 For example to setup an SSH or telnet connection
direct to the real server you need to pass that
through Piranha. Just setup a load balance of one real
server on the ssh or telnet port.

> Also I incidentally
> observe that if the default gateway of the
> realserver
> is down, nanny will not be able to contact the
> realserver too. (though still able to ping/telnet
> the
> RIP which I suppose don't go through the default
> gateway as I'm using DR/single network setup).

Right.  The default gateway on the real server SHOULD
BE SET TO the NAT IP ADDRESS of the Piranha server.

Sorry I did not fully reply to what you wanted.

Peter


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