What’s New in SingularityCE 4.0
This section highlights important changes in SingularityCE 4.0 that are of note to system administrators. See also the “What’s New” section in the User Guide for user-facing changes.
SingularityCE’s OCI-mode, which was experimental in 3.11, is now expanded and fully supported. It is enabled via
--ocion the command line, or by setting
oci mode = truein
OCI-mode runs containers unprivileged, using a low-level OCI runtime rather than SingularityCE’s own native runtime. SingularityCE’s setuid starter executable is not used on OCI-mode, even when setuid is enabled for the native runtime.
OCI-mode uses OCI-SIF images, a variant of the Singularity Image Format. These images cannot be run using earlier versions of SingularityCE.
OCI-mode supports the Container Device Interface (CDI) standard for enabling access to GPUs and other devices within containers.
squashfuse, which is now built from a git submodule unless
--without-squashfuseis specified as an argument to
mconfig. When built with
squashfuseshould be located on
PATH. Version 0.2.0 or later is required.
tar2sqfsto be installed on the system in order to create OCI-SIF images.
fuse-overlayfsto be installed on the system (from a distribution package), to fully support unprivileged overlays.
OCI-mode requires that either
crunis installed on the system (from a distribution package).
OCI-mode requires that subuid/subgid mappings have been configured for users, in the same manner as documented for the fakeroot feature.
RPM packages now use
/var/singularity) to store local state files.
Bash completions are now installed to the modern
share/bash-completion/completionslocation, rather than under
The keyserver management commands that were under remote have been moved to their own, dedicated keyserver command. Run
singularity help keyserverfor more information.
Caching of OCI blobs is now architecture aware. If older versions of SingularityCE are not being used in parallel, users should run
singularity cache cleanto recover space used by obsolete cached blobs.
Support for image driver plugins, deprecated at 3.11, has been removed. Unprivileged kernel overlay is supported without a plugin. In
image driverdirective has been removed, and
enable overlayno longer supports the