CRON Jobs Fail To Run w/PAM Error

Added a cron job to a service account's crontab using the standard crontab -e -u ogo command. This server has been chugging away for more than a year, with lots of stuff running within he service account - but nothing via cron.

Subsequently the cron jobs didn't run. :( The error logged in /var/log/cron was:

May 24 14:45:01 purple crond[18909]: (ogo) PAM ERROR (Authentication service cannot retrieve authentication info)

The issue turned out to be that the service account - which is a local account, not something from AD, LDAP, etc... - did not have a corresponding entry in /etc/shaddow. This breaks CentOS7's default PAM stack (specified in /etc/pam.d/crond). The handy utility pwck will fix this issue, after which I the jobs ran without error.

[root@purple ~]# pwck
add user 'ogo' in /etc/shadow? y
pwck: the files have been updated
[root@purple ~]# grep ogo /etc/shadow
ogo:x:18040:0:99999:7:::