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What is Charliecloud?

Charliecloud provides user-defined software stacks (UDSS) for high-performance computing (HPC) centers. This “bring your own software stack” functionality addresses needs such as:

  • software dependencies that are numerous, complex, unusual, differently configured, or simply newer/older than what the center provides;
  • build-time requirements unavailable within the center, such as relatively unfettered internet access;
  • validated software stacks and configuration to meet the standards of a particular field of inquiry;
  • portability of environments between resources, including workstations and other test and development system not managed by the center;
  • consistent environments, even archivally so, that can be easily, reliably, and verifiably reproduced in the future; and/or
  • usability and comprehensibility.

How does it work?

Charliecloud uses Linux user namespaces to run containers with no privileged operations or daemons and minimal configuration changes on center resources. This simple approach avoids most security risks while maintaining access to the performance and functionality already on offer.

Container images can be built using Docker or anything else that can generate a standard Linux filesystem tree.

How do I learn more?

Who is responsible?


How can I participate?

Use our GitHub page:

Bug reports and feature requests should be filed as “Issues”. Questions, comments, support requests, and everything else should use our “Discussions”. Don't worry if you put something in the wrong place; we’ll be more than happy to help regardless.

We also have a mailing list for announcements:

Patches are much appreciated on the software itself as well as documentation. Optionally, please include in your first patch a credit for yourself in the list above.

We are friendly and welcoming of diversity on all dimensions.

How do I cite Charliecloud?

If Charliecloud helped your research, or it was useful to you in any other context where bibliographic citations are appropriate, please cite the following open-access paper:

Reid Priedhorsky and Tim Randles. “Charliecloud: Unprivileged containers for user-defined software stacks in HPC”, 2017. In Proc. Supercomputing. DOI: 10.1145/3126908.3126925.

Note: This paper contains out-of-date number for the size of Charliecloud’s code. Please instead use the current number in the FAQ.

Charliecloud is copyright © 2014–2023 Triad National Security, LLC and others.

This software was produced under U.S. Government contract 89233218CNA000001 for Los Alamos National Laboratory (LANL), which is operated by Triad National Security, LLC for the U.S. Department of Energy/National Nuclear Security Administration.

This is open source software (LA-CC 14-096); you can redistribute it and/or modify it under the terms of the Apache License, Version 2.0. A copy is included in file LICENSE. You may not use this software except in compliance with the license.

The Government is granted for itself and others acting on its behalf a nonexclusive, paid-up, irrevocable worldwide license in this material to reproduce, prepare derivative works, distribute copies to the public, perform publicly and display publicly, and to permit others to do so.

Neither the government nor Triad National Security, LLC makes any warranty, express or implied, or assumes any liability for use of this software.

If software is modified to produce derivative works, such derivative works should be clearly marked, so as not to confuse it with the version available from LANL.