Minos does not have the resources to build and test our software under SL7,
and support for RedHat 6 ends in November 2020.
We plan to continue running under SL6 by using the Singulrity SL6 container provided by Fermilab.

Singularity runs as a user-space non-privileged image, so should be useful on any future systems.

This is key to our short term analysis needs, as well as Data Preservation concerns.


To run in a Singularity SL6 environment on Fermilab systems, run the script


Then source your .profile or .bashrc file.

You should then be able to run standard loon jobs, and build and run test releases.

We do not yet have a Centos 8 host available for testing Singularity.


From Art Kreymer issue 24897(

According to the document

it seems we need to start submitting jobs with

-l '+SingularityImage=\"/cvmfs/\"'

instead of


Working with a Test Release

From Art Kreymer issue 24897(

The Singularity image does not have a functional /etc/krb5.conf file,
so you cannot kinit or ssh from this environment.
Hence no access to CVS.

I have created a workaround :
We need to set an environment that uses a current krb5.conf,
and that does ssh with the appropriate default options.

export KRB5_CONFIG=/minos/app/scripts/krb5.conf
export CVS_RSH=/minos/app/scripts/cvsrsh


See development discussions in

We were guided by a talk by Marco Mambelli
the overall Singularity documentation at

and work by Annie, see notes on




The /minos/app/scripts/sing script is quit primitive, and does not source your .bashrc or .profile

NOvA is also using Singularity, via a more powerful script