snow, socket cluster: problem with path to rscript

Thu, Apr 16, 2009 1:52 AM

luke at stat.uiowa.edu a ?crit :

On Wed, 15 Apr 2009, Matthieu Stigler wrote:

Steve Weston a ?crit :

On Tue, Apr 14, 2009 at 5:29 AM, Matthieu Stigler
<matthieu.stigler at gmail.com> wrote:

So it is now working for the local computer with. However, when 
trying to
use the external computer, it seems to be working but nothing 
happens after
he asked for the last password...

This tells you is that "something went wrong".  The basic strategy 
in this case
is to use the "outfile" option to hopefully capture an error 
message.  You might
need to set outfile differently for different slaves, particularly if
you're starting
more than one on the same machine, but I suggest just starting one 
slave
on 210 to avoid the issue.  So do something like:

host210 <- list(host = "mat at 192.100.100.210", rscript = 
"/usr/bin/Rscript",

+                       outfile="/tmp/log.txt")

cl2 <- makeCluster(list(host210), type = "SOCK")

Ok, thanks for pointing out this methid.

I tried it and got following error message. This does not seem not be 
computer specific (tried to do it to other host 213, and from other 
host 213 to 212, always same error message):

starting worker for ubuntu:10187 Error in socketConnection(master, 
port = port, blocking = TRUE, open = "a+b") : unable to open connection

Calls: local ... slaveLoop -> recvData -> makeSOCKmaster -> 
socketConnection

In addition: Warning message:

In socketConnection(master, port = port, blocking = TRUE, open = 
"a+b") :

ubuntu:10187 cannot be opened

Execution halted


Is it related to ssh or snow? I did not find any reference to that 
prob googling for it...

It is an issue with your ability to make a socket connection to the
master. Most likely the master computer has a firewall that is
blocking connections to the port snow uses.  Try turning the firewall
off or at least enabling the port in the error message.
A simple test is to do

    socketConnection(port = 10187, server = TRUE)

in an R session on the master and

    telnet ubuntu 10187

in a shell on your worker machine (assumign your master is called
ubuntu) (or you can use R and

    socketConnection("ubuntu", port = 10187)

in an R session on the worker).

luke

Thanks Luke and Dirk for your help!

I don't think it is a firewall error, as both machines have all port 
open (as default with iptables as I understood), and the admin of the 
network opened even port 10187.

I tried first the three solutions suggested, none of them seem to give 
good results:

$telnet 192.100.100.212 10187

Trying 192.100.100.212...

telnet: Unable to connect to remote host: Connection refused

R>socketConnection(port = 10187, server=TRUE)

#nothing happens... is it right?


R > socketConnection("192.100.100.212", port = 10187) 

Erreur dans socketConnection("192.100.100.212", port = 10187) : 

  impossible d'ouvrir la connexion

De plus : Warning message:

In socketConnection("192.100.100.212", port = 10187) :

  192.100.100.212:10187 cannot be opened

Same error message when using "ubuntu"/ dsge at 192.100.100.212 etc..

Going to a ubuntu forum, someone told that one has to open a server on 
the port (excuse, explanations are not good as I don't understand that 
much the subject :-( ).
So launching in the master (212):

$nc -l -p 10187


then one is able to  have in 210:

$telnet 192.100.100.212 10187

Trying 192.100.100.212...

Connected to 192.100.100.212.

Escape character is '^]'.

So it seems that it is working, but there is then no effect on the 
previous commands socketConnection, makeCluster, still claims that 10187 
can't be open.

With those elements, do you guys see clearer or is it even darker? 
Thanks a lot for your help!

Matthieu

snow, socket cluster: problem with path to rscript

Thread (18 messages)