After converting a system to sssd with an IPA backend, we found that cron was not
recognizing our users. It appears (based on using lsof to see what .so files are open)
that cron is reading nsswitch.conf at startup, and doesn’t notice the change when sssd
setup adds sss to the user map in nsswitch.conf. Restarting cron fixes it, but we’ve now
got another Ubuntu-specific hack in our Ansible setup script.