planning to migrate a Linux-Server enviroment to SLES12. But stuck how
to migrate the centralized logging.

It seems there are two solutions:
a) use rsyslog environment at SLES12. (the old fashion way)
b) check out journald a little bit and use the new systemd-journal-gatewayd.

The last seems to be an interesting way but where is
systemd-journal-gatewayd at SLES12? Have I to install special repos?