syslog-ng can be installed in replacement of rsyslog.
The syslog-ng-core package can be installed with the following command:
$ apt-get install syslog-ng-core
The syslog-ng-core package provides the syslog-ng daemon, which provides system logging services.
The syslog-ng service (in replacement of rsyslog) provides syslog-style logging by default on Debian.
The syslog-ng service can be enabled with the following command:
$ sudo systemctl enable syslog-ng.service
The syslog-ng service must be running in order to provide logging services, which are essential to system administration.