---
title: OAR
description: Reference for the oar executor, which submits tasks to the OAR resource manager.
---

# OAR

The `oar` executor runs pipeline tasks using the [OAR](https://oar.imag.fr) resource manager. It submits each task as an OAR job using the `oarsub` command.

To enable the OAR executor, set `process.executor = 'oar'` in the `nextflow.config` file. Launch the pipeline from a node where `oarsub` is available, typically the cluster login node.

Use the following process directives to control resource requests and other job characteristics:

- [clusterOptions][process-clusteroptions]
- [cpus][process-cpus]
- [memory][process-memory]
- [queue][process-queue]
- [time][process-time]

When you specify `clusterOptions` as a string, separate multiple options with semicolons so that the job script is formatted correctly:

```groovy
clusterOptions = '-t besteffort;--project myproject'
```

<AddedInVersion version="24.04" />

You can also specify the options as a string list:

```groovy
clusterOptions = [ '-t besteffort', '--project myproject' ]
```

See [clusterOptions][process-clusteroptions] for details.

[process-clusteroptions]: ../reference/process#clusteroptions
[process-cpus]: ../reference/process#cpus
[process-memory]: ../reference/process#memory
[process-queue]: ../reference/process#queue
[process-time]: ../reference/process#time
