[R] package Parallel - accessing remote cores on Windows using plink (PuTTY)

Tevlin, Dylan
Fri, 19 Sep 2014 14:49:36 -0000

Hello all.

My system information:

R 2.14.1 x64
Windows 7

I'm attempting to access cores on other machines in my LAN.  As setup, I can
ping all the machines successfully and it's a private office network where I
have access to all computers, so there really shouldn't be any problems
arising from the network itself.

All machines I am connecting to have identical system information.

I issue the following command to make a connection to the remote machine and
access one of its cores.

cl<-makePSOCKcluster(c(remoteHostIP), rshcmd="plink",
outfile="")

The parallel package, to make remote connections, issues a system command (found
in the file snowSOCK.R, function newPSOCKnode of the source) of the following
form on the remote machine

ssh -l user otherhost '/usr/lib/R/bin/Rscript' -e
'parallel:::.slaveRSOCK()' MASTER=myhost PORT=10187 OUT=/dev/null
TIMEOUT=2592000 METHODS=TRUE XDR=TRUE

Where the specific command (ssh) can be specified by the rshcmd parameter of the
command makePSOCKcluster.  Given that a command such as ssh must be present on
the machine, I installed PuTTY on both the master and host, and added the
pertinent path to the system PATH variable so that plink is always accessible
from the command line.   I'm not set on PuTTY, it's just free and
I've used it before.

Here are my two cases.  If I issue my above command, the process hangs
indefinitely.  If I set the manual flag equal to TRUE, as in the following

cl<-makePSOCKcluster(c(remoteHostIP), rshcmd="plink",
outfile="", manual=TRUE)

I'm able to make the connection to the remote host just fine.  This
indicates to me that there is something wrong with the system command that is
being issued with manual=FALSE (the default).

Another problem with this is that it is seemingly very hard to test, as the
hanging process gives me no information on what is actually occurring.  Has
anyone had any success with this?  Are there any ideas on steps I could take to
fix or debug this issue?

Regards,

Dylan



Dylan Tevlin
(480) 419-3611


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