Pluggable authentication modules (PAM) are the core of the user authentication in any modern Linux distribution.

The pam_passwdqc and pam_ecryptfs modules were removed between Red Hat Enterprise Linux 6 and Red Hat Enterprise Linux 7, which made some PAM configuration files no longer valid.

The Preupgrade Assistant comments out these modules in your PAM configuration
files after the in-place upgrade automatically, but review and
regain the authentication functionality in a different way, if these modules were
required for your authentication policy.
