slaves are spawned successfully but on single node only.

[sunracesuraj]

Hello,

I came across a post - http://borisv.lk.net/howtos/grid-mpi-r-howto.html
I have managed to get R running on Rocks 7 and now I am stuck at following stage - did anyone face this problem? If yes then did anyone ever solve it?

Basically only one host is being used to spawn the slaves.

I get this result for the given code.

Code - 1

detectCores.R script

library(Rmpi)
library('parallel')
cl <- makeCluster(2,type="MPI")
clusterCall(cl, function() Sys.info()[c("nodename","machine")])
stopCluster(cl)
mpi.quit()

Result -
[root@front rolltests]# Rscript detectCores.R
2 slaves are spawned successfully. 0 failed.
[[1]]
nodename machine
"front.attr1.kw" "x86_64"

[[2]]
nodename machine
"front.attr1.kw" "x86_64"

Code 2
detectCores.R script
library(Rmpi)
library('parallel')
n.cores <- mpi.universe.size()
cl <- makeCluster(n.cores, type='MPI')
result <- parLapply(cl, 1:n.cores,
function (i) {system2('hostname', stdout=TRUE)})
summary(factor(unlist(result)))
stopCluster(cl)
mpi.quit()

Result -
[root@front rolltests]# Rscript detectCores.R
1 slaves are spawned successfully. 0 failed.
front.attr1.kw
1

I also came across this post - is this related?

https://stackoverflow.com/questions/30470443/initialize-mpi-cluster-using-rmpi

It will be great help if someone could guide me in the right direction.