To be able to monitor the credential mappings, first uncomment this line from the /etc/gss/gsscred.conf file.
SYSLOG_UID_MAPPING=yes
Next, make the gssd service read the /etc/gss/gsscred.conf file.
# pkill -HUP gssd
Now you can monitor the credential mappings as gssd requests them. The mappings are recorded by the rsyslog daemon, if the rsyslog.conf file is configured for the auth system facility with the debug severity level.