Provided by: charliecloud-common_0.37-1build1_all 
NAME
charliecloud - Lightweight user-defined software stacks for high-performance computing
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?
• Documentation: https://hpc.github.io/charliecloud
• GitHub repository: https://github.com/hpc/charliecloud
• Low-traffic mailing list for announcements: https://groups.io/g/charliecloud
• We wrote an article for USENIX’s magazine ;login: that explains in more detail the motivation for
Charliecloud and the technology upon which it is based:
https://www.usenix.org/publications/login/fall2017/priedhorsky
• For technical papers about Charliecloud, refer to the Technical publications section below.
WHO IS RESPONSIBLE?
Contributors:
• Richard Berger <rberger@lanl.gov>
• Lucas Caudill <lcaudill@lanl.gov>
• Rusty Davis <rustyd@lanl.gov>
• Hunter Easterday <heasterday@lanl.gov>
• Oliver Freyermuth <o.freyermuth@googlemail.com>
• Shane Goff <rgoff@lanl.gov>
• Michael Jennings <mej@lanl.gov>
• Christoph Junghans <junghans@lanl.gov>
• Dave Love <dave.love@manchester.ac.uk>
• Jordan Ogas <jogas@lanl.gov>
• Kevin Pelzel <kpelzel@lanl.gov>
• Megan Phinney <mphinney@lanl.gov>
• Reid Priedhorsky <reidpr@lanl.gov>, co-founder and project lead
• Tim Randles <trandles@lanl.gov>, co-founder
• Benjamin “The Storm” Stormer <bstormer@lanl.gov>
• Meisam Tabriz <meisam.tabriz@mpcdf.mpg.de>
• Matthew Vernon <mv3@sanger.ac.uk>
• Peter Wienemann <wienemann@physik.uni-bonn.de>
• Lowell Wofford <lowell@lanl.gov>
HOW CAN I PARTICIPATE?
Use our GitHub page: https://github.com/hpc/charliecloud
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: https://groups.io/g/charliecloud
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.
TECHNICAL PUBLICATIONS
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.
Other publications:
• We compare the performance of three HPC-specific container technologies against bare metal, finding no
concerns about performance degradation.
Alfred Torrez, Tim Randles, and Reid Priedhorsky. “HPC container runtimes have minimal or no
performance impact”, 2019. In Proc. CANOPIE HPC Workshop @ SC. DOI:
10.1109/CANOPIE-HPC49598.2019.00010.
• A demonstration of how low-privilege containers solve increasing demand for software flexibility.
Reid Priedhorsky, R. Shane Canon, Timothy Randles, and Andrew J. Younge. “Minimizing privilege for
building HPC containers”, 2021. In Proc. Supercomputing. DOI: 10.6084/m9.figshare.14396099.
• Charliecloud’s build cache performs competitively with the standard many-layered union filesystem
approach and has structural advantages including a better diff format, lower cache overhead, and better
file de-duplication.
Reid Priedhorsky, Jordan Ogas, Claude H. (Rusty) Davis IV, Z. Noah Hounshel, Ashlyn Lee, Benjamin
Stormer, and R. Shane Goff. “Charliecloud’s layer-free, Git-based container build cache”, 2023. In
Proc. Supercomputing. DOI: 10.1145/3624062.3624585.
COPYRIGHT AND LICENSE
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.
Reporting bugs
If Charliecloud was obtained from your Linux distribution, use your distribution’s bug reporting
procedures.
Otherwise, report bugs to: https://github.com/hpc/charliecloud/issues
SEE ALSO
ch-checkns(1), ch-completion.bash(7), ch-convert(1), ch-fromhost(1), ch-image(1), ch-run(1),
ch-run-oci(1), ch-test(1),
Full documentation at: https://hpc.github.io/charliecloud
NOTE
These man pages are for Charliecloud version 0.37 (Git commit 0.37).
COPYRIGHT
2014–2023, Triad National Security, LLC and others