Treffer: Apptainer Without Setuid.

Apptainer (formerly known as Singularity) since its beginning implemented many of its container features with the assistance of a setuidroot program. It still supports that mode, but as of version 1.1.0 it no longer uses setuid by default. This is feasible because it now can mount squashfs filesystems, ext3 filesystems, and overlay filesystems using unprivileged user namespaces and FUSE. It also now enables unprivileged users to build containers, even without requiring system administrators to configure /etc/subuid and /etc/subgid unlike other "rootless" container systems. As a result, all the unprivileged functions can be used nested inside of another container, even if the container runtime prevents any elevated privileges. As of version 1.2.0 Apptainer also supports completely unprivileged encryption of Singularity Image Format (SIF) container files. Performance with a particularly challenging HEP benchmark using the FUSE-based mounts both with and without encryption is essentially identical to the previous methods that required elevated privileges to use the Linux kernel-based counterparts. [ABSTRACT FROM AUTHOR]

Copyright of EPJ Web of Conferences is the property of EDP Sciences and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)