---
name: "oarsh"
section: "1"
platform: "linux"
package: "oar-common"
version: "2.6.1-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/oarsh"
---

# oarsh(1)

remote shell connector for OAR batch scheduler. oarcp - oarsh companion to copy files from a node or to a node.

## NAME

oarsh - remote shell connector for OAR batch scheduler.

oarcp - oarsh companion to copy files from a node or to a node.

## SYNOPSIS

**oarsh** \[OPTIONS\] \<NODENAME\> \[COMMAND\]

**oarcp** \[OPTIONS\] \[NODENAME:\]\<PATHNAME\> \[NODENAME:\]\<PATHNAME\>

## DESCRIPTION

Connect to a node from the job submission frontend of the cluster or any other node.

## OPTIONS

The **oarsh** mechanism uses *OpenSSH* client (the ssh command) under the hood to perform connections to remote hosts. Thus most of *OpenSSH* options can be used (but some are filtered out for security reasons).

## ENVIRONMENT

- **OAR\_JOB\_ID**

  If not using the job-key mechanism, the **OAR\_JOB\_ID** environment variable has to be set to give the jobid of the job to connect to on the remote node (a node can run several jobs at a same time). This is only required for connecting from outside the job (e.g. from the job submission frontend).

- **OAR\_JOB\_KEY\_FILE**

  If using the job-key mechanism (see **oarsub** -k -e/-i), **oarsh** can use the job-key defined by the **OAR\_JOB\_KEY\_FILE** environment variable to connect to job on the remote machine. That mechanism can allow one to connect to a job from a machine which is outside the OAR cluster the job belong to (e.g. in a grid of OAR clusters), given the job-key is available on that machine. NB: it is also possible to give the job-key using **oarsh** -i option.

- **OAR\_USER\_CPUSET**

  Setting the **OAR\_USER\_CPUSET** environment variable for **oarsh** allows running the process in the target node with a subset of the CPU set of the job. Expected format for **OAR\_USER\_CPUSET** is a list of , or + or space separated processing unit. The processing unit ids of the job can be shown using **oarprint** (*cpuset* property), or more generally with hwloc's **lstopo** command (physical PU). The **oarnodes** command also shows the *cpuset* resource property for every OAR resource.

- **OAR\_USER\_GPUDEVICE**

  If the GPU device mechanism is enabled in the OAR installation, setting the **OAR\_USER\_GPUDEVICE** environment variable for **oarsh** allows running the process in the target node with a subset of the GPU devices of the job. Expected format for **OAR\_USER\_GPUDEVICE** is a list of , or + or space separated Linux char devices (e.g.: */dev/nvidia0*). The GPU devices of the job can be shown with using **oarprint** (*gpudevice* property). The **oarnodes** command also shows the *gpudevice* resource property for every OAR resource.

## EXAMPLES

- Connecting from within our job, from one node to another one (node23):

  ```
   oarsh node-23
  ```

- Connecting to a node (node23) of our job (Id: 4242) from the frontal of the cluster:

  ```
   OAR_JOB_ID=4242 oarsh node-23
  ```

- Connecting to a node (node23) of our job that was submitted using a job-key, possibly from anywhere:

  ```
   OAR_JOB_KEY_FILE=~/my_key oarsh node-23
  ```

- Same thing but using OpenSSH-like *-i* option:

  ```
   oarsh -i ~/my_key node-23
  ```

- Running a process on a subset of the CPU set of GPU devices of the job:

  ```
   OAR_USER_CPUSET=0,7 OAR_USER_GPUDEVICE=/dev/nvidia3 oarsh node-23
  ```

## NOTES

**oarsh** inherits from most of OpenSSH capabilities (e.g. X11 forwarding). However, one feature which **oarsh** does break is the SSH Agent.

The user's OpenSSH configuration files (files in the *~/.ssh* directory) are not used by **oarsh**.

When a job is running alone on a whole host, it may be possible to simply use **ssh** instead of **oarsh** to connect to the host. This require OAR to be configured with the **pam\_oar\_adopt** mechanism.

## SEE ALSO

[**oarprint**(1)](/oarprint/1.md), [**oarnodes**(1)](/oarnodes/1.md), [**lstopo**(1)](/lstopo/1.md), [**ssh**(1)](/ssh/1.md), [**oarcp**(1)](/oarcp/1.md), [**oarsub**(1)](/oarsub/1.md), [**pam\_oar\_adopt**(8)](/pam_oar_adopt/8.md)

## COPYRIGHTS

```
 Copyright 2003-2025 Laboratoire d'Informatique de Grenoble (http://www.liglab.fr). This software is licensed under the GNU General Public License Version 2 or above. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
```