[scyld-users] RE: Help! Endless RARP requests

velthuis at fisher.biology.rochester.edu velthuis at fisher.biology.rochester.edu
Sun Aug 24 10:50:06 PDT 2003

Hello Gregg,

Here are some suggestions...

Are you using a cross-over cable to connect the two PC's? direct
connections need a different cable than is used when connecting via hub or
switch. If a node can not reach the master (or, more accurately can not
reach the bpserv deamon running on the master) it defaults to rebooting
and will try again.

During installation on your master, which eth port did you specify for the
Beowulf network? (Assuming you used defaults throughout you can check your
network is up by doing e.g. a 'ifconfig' or a 'netstat -rn' and look for
confirmation that ipaddress is up, and that you can 'ping' it
etc.) Ok, you wrote that this seems to works.

Next, do a 'ps ax' on the master to check that the bpserv deamon is
running as it should. Pay attention during startup of the master for any
indication that perhaps something is going wrong that leads to this server
deamon to not being started automatically. (A 'dmesg' or a 'cat
/var/log/messages' may be useful to check startup messages if they went by
too fast. Alternatively pressing 'shift/page up' during boot should let
you browse back thru messages that went of the screen already) Similar for
any indication that your network is actually up and running as you state
it is. Are you convinced that your ethernet cards function properly? E.g.
if you would install any operating system on these two machines, would you
be able to 'ping' from one to the other and vice versa using your current
cable? Here it would help to check the LEDs on both ethernet cards. Are
they both flashing when your node tries to reach the master?

Hope any of these tips will get you going again. Good luck!


> Date: Sat, 23 Aug 2003 13:02:32 -0400
> From: Gregg Germain <saville at comcast.net>
> To: scyld-users at beowulf.org
> Subject: [scyld-users] Help! Endless RARP requests
> Hi,
>  I have the SCYLD Beowulf Basic edition (Red Hat 6.2) which I got from
> Linux Central.
>  I installed it on a PC with 2 ethernet cards.
>  The installation went gret. Next I connected another PC to the Master
> node by dirctly connecting the slave nodes eth0 card to the Master
> Node's eth1 card.
>  I then booted the slave node using the SCYLD CD.  Booting seems to go
> well but thren it gets to the point where it's making RARP requests and
> it stays there forever. Eventually the slave node reboots itself and
> then gets stuck inthe RARP request once again.
>  Can anyone give me a hint as to what I need to do to get the master
> node to respond?
> an /sbin/ifconfig on the master node shows that the eth1 card is active
> and operating in the range selected at install time.
>  Do I need to connect through a hub? I know I have to get on eventually
> for the second slave, but I thought I coudl get the first one going
> without a hub.
> thanks for any help yu can give.
> Gregg

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