The default format for the time and date in a log files created by rsyslog is:
Sep 30 16:12:55 mailer postfix/master[12008]: daemon started – version 3.3.0, configuration /etc/postfix
You’ll notice no year!
To get precision timestamped logs like this:
2019-10-02T13:34:40.136604-04:00 mailer postfix/qmgr[1749]: 56B1110200A: removed
edit /etc/rsyslog.conf and comment out this line:
#$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
Then restart rsyslog with:
service rsyslog restart
Colin