Abstract
Petascale simulations on the largest supercomputers in the US require
advanced data management techniques in order to optimize the application scien-
tist time, and to optimize the time spent on the supercomputers. Researchers in
such problems are starting to require workflow automation during their simula-
tions in order to monitor the simulations, and in order to automate many of the
complex analysis which must take place from the data that is generated from these
simulations. Scientific workflows are being used to monitor simulations running
on these supercomputers by applying a series of complex analysis, and finally
producing images and movies from the variables produced in the simulation, or
from the derived quantities produced by the analysis. The typical scenario is
where the large calculation runs on the supercomputer, and the auxiliary diagnos-
tics/monitors are run on resources, which are either on the local area network of
the supercomputer, or over the wide area network. The supercomputers at one of
the largest centers are highly secure, and the only method to log into the center is
interactive authentication by using One Time Passwords (OTP) that are generated
by a security device and expire in half a minute. Therefore, grid certificates are not
a current option on these machines in the Department of Energy at Oak Ridge Na-
tional Laboratory. In this paper we describe how we have extended the Kepler sci-
entific workflow management system to be able to run operations on these
supercomputers, how workflows themselves can be executed as batch jobs, and fi-
nally, how external data-transfer operations can be utilized when they need to per-
form authentication for their own as well.
