  We show that distributed Infrastructure-as-a-Service (IaaS) compute clouds
can be effectively used for the analysis of high energy physics data. We have
designed a distributed cloud system that works with any application using large
input data sets requiring a high throughput computing environment. The system
uses IaaS-enabled science and commercial clusters in Canada and the United
States. We describe the process in which a user prepares an analysis virtual
machine (VM) and submits batch jobs to a central scheduler. The system boots
the user-specific VM on one of the IaaS clouds, runs the jobs and returns the
output to the user. The user application accesses a central database for
calibration data during the execution of the application. Similarly, the data
is located in a central location and streamed by the running application. The
system can easily run one hundred simultaneous jobs in an efficient manner and
should scale to many hundreds and possibly thousands of user jobs.
