configure logrotate to not delete log files after rotation

copy: Make a copy of the log file, but don’t change the original at all.
copytruncate: Truncate the original log file in place after creating a copy.

An example: /etc/logrotate.d/mds

/var/log/mds/mds-app-*.log {
    daily
    copytruncate
    rotate 30
    dateext
    missingok
    notifempty
    sharedscripts
}