# 9. Launching applications

PRRTE can launch processes in a wide variety of environments, but they can generally be broken down into two categories:

1. Scheduled environments: these are systems where a resource manager and/or scheduler are used to control access to the compute nodes. Popular resource managers include Slurm, PBS/Pro/Torque, and LSF.

2. Non-scheduled environments: these are systems where resource managers are not used. Launches are typically local (e.g., on a single laptop or workstation) or via `ssh` (e.g., across a small number of nodes).

PRRTE provides two commands for starting applications:

1. `prun` - submits the specified application to an existing persistent DVM for execution. The DVM continues execution once the application has completed. The prun command will remain active until the application completes. All application and error output will flow through prun.

2. `prterun` - starts a DVM instance and submits the specified application to it for execution. The DVM is terminated once the application completes. All application and error output will flow through prterun.

The rest of this section usually refers only to `prterun`, even though the same discussions also apply to `prun` because the command line syntax is identical.

- 9.1. Quick start: Launching applications
- 9.2. Prerequisites
- 9.3. Placing processes across hosts
- 9.4. Fundamentals
- 9.5. Launching only on the local node
- 9.6. Launching with SSH
- 9.7. Launching with Slurm
- 9.8. Launching with LSF
- 9.9. Launching with PBS / Torque
- 9.10. Launching with Grid Engine
- 9.11. Unusual jobs
- 9.12. Troubleshooting