Scalable cluster administration Python framework — Manage node sets, node groups and execute commands on cluster nodes in parallel.
Python Shell
Latest commit 65485ac Dec 21, 2016 @degremont degremont (#239) Use 'except ... as' syntax wherever needed
Use the 'except Exception as variable' syntax for all try/except
in the code.

This breaks compatibility with Python 2.4 and 2.5!

Change-Id: Ic1ddb6f21c6c972009e37ce3fbfd7c3955c337bf

ClusterShell 1.7 Python Library and Tools

ClusterShell is an event-driven open source Python library, designed to run local or distant commands in parallel on server farms or on large Linux clusters. It will take care of common issues encountered on HPC clusters, such as operating on groups of nodes, running distributed commands using optimized execution algorithms, as well as gathering results and merging identical outputs, or retrieving return codes. ClusterShell takes advantage of existing remote shell facilities already installed on your systems, like SSH.

ClusterShell's primary goal is to improve the administration of high- performance clusters by providing a lightweight but scalable Python API for developers. It also provides clush, clubak and nodeset, three convenient command-line tools that allow traditional shell scripts to benefit from some of the library features.

Requirements (v1.7)

  • GNU/Linux, BSD, Mac OS X
  • OpenSSH (ssh/scp) or rsh
  • Python 2.x (x >= 4)
  • PyYAML (optional)


ClusterShell is distributed under the GNU Lesser General Public License version 2.1 or later (LGPL v2.1+). Read the file COPYING.LGPLv2.1 for details.


Online documentation is available here:

The Sphinx documentation source is available under the doc/sphinx directory. Type 'make' to see all available formats (you need Sphinx installed and sphinx_rtd_theme to build the documentation). For example, to generate html docs, just type:

make html BUILDDIR=/dest/path

For local library API documentation, just type:

$ pydoc ClusterShell

The following man pages are also provided:

clush(1), clubak(1), nodeset(1), clush.conl(5), groups.conf(5)

Test Suite

Regression testing scripts are available in the 'tests' directory:

$ cd tests
$ nosetests -sv <>
$ nosetests -sv --all-modules

You have to allow 'ssh localhost' and 'ssh $HOSTNAME' without any warnings for "remote" tests to run as expected. $HOSTNAME should not be nor ::1. Also some tests use the 'bc' command.

ClusterShell interactively

>>> from ClusterShell.Task import task_self
>>> from ClusterShell.NodeSet import NodeSet
>>> task = task_self()
>>>"/bin/uname -r", nodes="linux[4-6,32-39]")
<ClusterShell.Worker.Ssh.WorkerSsh object at 0x20a5e90>
>>> for buf, key in task.iter_buffers():
...     print NodeSet.fromlist(key), buf

linux[4-6] 2.6.32-71.el6.x86_64


Web site:

Online documentation:

Github source respository:

Github Wiki:

Github Issue tracking system: project page:

Python Package Index (PyPI) link:

ClusterShell was born along with Shine, a scalable Lustre FS admin tool:

Core developers/reviewers

  • Stephane Thiell
  • Aurelien Degremont
  • Henri Doreau
  • Dominique Martinet

CEA/DAM 2010, 2011, 2012, 2013, 2014, 2015 -