A Morning With Ganga

I (finally) downloaded and installed ganga onto one of the cluster UIs. It's a cinch to install, just run one python script, add an element to your PATH and you're away.

The next step is going through the User Guide. Although this was written for 4.2, there's nothing I found which didn't basically work in 4.3.1.

It's quite easy to setup and run simple jobs:

In [2]:j=Job(application=Executable(exe='/bin/echo',args=['Hello, World']))

In [3]:j.submit()
Ganga.GPIDev.Lib.Job               : INFO     submitting job 0
Ganga.GPIDev.Adapters              : INFO     submitting job 0 to Local backend
Ganga.GPIDev.Lib.Job               : INFO     job 0 status changed to "submitted"
Out[3]: 1

In [4]:outfile=file(j.outputdir+'stdout')
Ganga.GPIDev.Lib.Job               : INFO     job 0 status changed to "running"
Ganga.GPIDev.Lib.Job               : INFO     job 0 status changed to "completed"

In [5]:print outfile.read()
Hello, World

However, that's spawning a job which just runs on the local machine - how easy was it to run on the grid?

Answer: very easy!

In [39]:l1=Job(backend=LCG())
In [42]:l1.application=Executable(exe='/bin/echo',args=['Hello, World'])

In [44]:l1.submit()
Ganga.GPIDev.Lib.Job               : INFO     submitting job 3
Ganga.GPIDev.Adapters              : INFO     submitting job 3 to LCG backend
Ganga.GPIDev.Lib.Job               : INFO     job 3 status changed to "submitted"
Out[44]: 1

In [45]:l1.status
Out[45]: submitted

In [46]:l1.backend 
Out[46]: LCG (
 status = 'Ready' ,
 reason = 'unavailable' ,
 iocache = '' ,
 CE = None ,
 middleware = 'EDG' ,
 actualCE = 'ce.ulakbim.gov.tr:2119/jobmanager-lcgpbs-dteam' ,
 id = 'https://svr023.gla.scotgrid.ac.uk:9000/-wOjj5xKfjcrKIXiCEISNA' ,
 jobtype = 'Normal' ,
 exitcode = None ,
 requirements = LCGRequirements (
    other = [] ,
    nodenumber = 1 ,
    memory = None ,
    software = [] ,
    ipconnectivity = 0 ,
    cputime = None ,
    walltime = None
    )
 )
In [52]:
Ganga.GPIDev.Lib.Job               : INFO     job 3 status changed to "completing"
Ganga.GPIDev.Lib.Job               : INFO     job 3 status changed to "completed"

In [54]:print file(l1.outputdir+'stdout').read()
Hello, World

Wonderful! Didn't have to do any of that nasty edg-job-* stuff. And it ran in Turkey - pretty cool.

I have also now discovered how to define and submit batches of jobs to the grid. This snippet defines a set of 10 jobs:

a=list()
for i in range(10):
    a.append(Executable(exe='/bin/echo', args=[str(i)]))
s=ExeSplitter(apps=a)
j=Job(splitter=s,backend=LCG())
j.submit()

Submitted that and I'm running jobs in China, Italy, Greece, Pakistan, Russia, Austria, France, Spain and Switzerland.

I think this is the first time in a while I've thought "Hey! The grid is actually cool."