Start multiple h2o cluster from within R

Question

My intention is to start two or more h2o clusters / instances (not two or more nodes!) from within R on the same computer/server to enable multiple user to connect with h2o at the same time. In addition, I want to be able to shutdown and restart clusters separately, also from within R.

I already know that I cannot controll multiple h2o clusters simply from within R, thus I tried to start two clusters from the command line in Windows 10:

java -Xmx1g -jar h2o.jar -name testCluster1 -nthreads 1  -port 54321
java -Xmx1g -jar h2o.jar -name testCluster2 -nthreads 1  -port 54323

This works fine for me:

library(h2o)

h2o.init(startH2O = FALSE, ip = "localhost", port = 54321) 
Connection successful!

R is connected to the H2O cluster: 
H2O cluster uptime:         4 minutes 8 seconds 
H2O cluster version:        3.8.3.2 
H2O cluster name:           testCluster 
H2O cluster total nodes:    1 
H2O cluster total memory:   0.87 GB 
H2O cluster total cores:    4 
H2O cluster allowed cores:  1 
H2O cluster healthy:        TRUE 
H2O Connection ip:          localhost 
H2O Connection port:        54321 
H2O Connection proxy:       NA 
R Version:                  R version 3.2.5 (2016-04-14) 

h2o.init(startH2O = FALSE, ip = "localhost", port = 54323)
Connection successful!

R is connected to the H2O cluster: 
H2O cluster uptime:         3 minutes 32 seconds 
H2O cluster version:        3.8.3.2 
H2O cluster name:           testCluster2 
H2O cluster total nodes:    1 
H2O cluster total memory:   0.87 GB 
H2O cluster total cores:    4 
H2O cluster allowed cores:  1 
H2O cluster healthy:        TRUE 
H2O Connection ip:          localhost 
H2O Connection port:        54323 
H2O Connection proxy:       NA 
R Version:                  R version 3.2.5 (2016-04-14) 

Now, I want to do the same from within R via the system() command.

launchH2O <-  as.character("java -Xmx1g -jar h2o.jar -name testCluster -nthreads 1  -port 54321")
system(command = launchH2O, intern =TRUE)

But I get an error message:

[1] "Error: Unable to access jarfile h2o.jar"
attr(,"status")
[1] 1
Warning message:
running command 'java -Xmx1g -jar h2o.jar -name testCluster -nthreads 1  -port 54321' had status 1 

Trying

system2(command = launchH2O)

I get a warning message and I am not able to connect with the cluster:

system2(command = launchH2O)
Warning message:
running command '"java -Xmx1g -jar h2o.jar -name testCluster -nthreads 1  -port 54321"' had status 127 

h2o.init(startH2O = FALSE, ip = "localhost", port = 54321)
Error in h2o.init(startH2O = FALSE, ip = "localhost", port = 54321) : 
Cannot connect to H2O server. Please check that H2O is running at http://localhost:54321/

Any ideas how to start / shutdown two or more h2o clusters from within R? Thank you in advance!

Note 1: I am only using my local Windows device for testing, I actually want to create multiple h2o clusters on a Linux server.

Note 2: I tried it with both R GUI (3.2.5) and R Studio (Version 0.99.892) and I ran them as admin. The h2o.jar file is in my working directory and my Java version is (Build 1.8.0_91-b14).

Note 3: System information: - h2o & h2o R package version: 3.8.3.2 - Windows 10 Home, Version 1511 - 16 RAM, Intel Core i5-6200U CPU with 2,30 GHz

Answer 1

EDIT: I've changed to intern=FALSE, in below examples, based on comments

---

You should just need to change directory; it is either that or not setting wait=FALSE (to run the command in the background).

launchH2O <- "java -Xmx1g -jar h2o.jar -name testCluster -nthreads 1 -port 54321"
savewd <- setwd("/path/to/h2ojar/")
system(command = launchH2O, intern =FALSE wait=FALSE)
setwd(savewd)

The last line, and the assignment to savewd is just to preserve working directory. Alternatively this should also work:

launchH2O <- "java -Xmx1g -jar /path/to/h2ojar/h2o.jar -name testCluster -nthreads 1 -port 54321"
system(command = launchH2O, intern =FALSE, wait=FALSE)

When on Linux, there is another way:

launchH2O <- "bash -c 'nohup java -Xmx1g -jar /path/to/h2ojar/h2o.jar -name testCluster -nthreads 1 -port 54321 &'"
system(command = launchH2O, intern =FALSE)

(Because the last command explicitly puts it in the background, I don't think you need to set wait=FALSE.)