crun bug affecting OCI-mode usage with SingularityCE 4.1.2

[David Trudgian]

All,

If you are running SingularityCE 4.1.2, you may see an unknown version specified error when using OCI-mode on systems with crun <1.14.3 installed.

Necessary updates to SingularityCE's chain of dependencies in version 4.1.2 mean that it now uses OCI runtime-spec 1.2.0 in OCI-mode. Unfortunately, crun <1.14.3, contains a version check bug that causes the error above.

Functionality can be restored by:

• Installing the latest version of crun from GitHub manually, and making it availabile to SingularityCE on PATH ahead of the older distro version.
  
• Removing crun and ensuring runc is installed, so that SingularityCE falls back to runc instead.
• Waiting until your distribution updates to a newer version of crun.

You are most likely to be affected if you install SingularityCE on RHEL / Alma Linux / Rocky Linux 8 or 9, as crun is suggested on these distributions in order to support the `--no-setgroups` flag, that preserves access to host files via supplementary groups.

In the event that EL distributions do not update crun soon, we will provide a more complete automatic fall-back in the next SingularityCE release. However, we note that a new version of crun that fixes the issue is making its way through CentOS Stream at this point.