LANL led with LLNL contributors, Charliecloud provides user-defined software stacks for HPC centers. It uses Linux user namespaces to run containers with no privileged operations or daemons and minimal configuration changes on center resources. Version 0.14 introduces internal code to pull images from a remote repository. skopeo and umoci are no longer required to build images using the fully unprivileged
ch-grow builder, which simplifies installation and configuration.