Update 04/27/2023: We have restored the overlay functionality on all Expanse nodes. 

Original message:

In response to a security advisory, we have disabled the overlay kernel module on all Expanse nodes. This will prevent the use of some Singularity containers and possibly CVMFS mounts on Expanse. We are working on a mitigation approach and will update once this functionality is restored. Please send a ticket via ACCESS support (https://support.access-ci.org) or SDSC's support email (consult@sdsc.edu) if you have any questions.

Thanks,

SDSC User Services Staff