Using zypper, install fail2ban and python-systemd rpms.
To install fail2ban software on systemd backend and journalctl syslog manager enable, in jail.conf:
backend = systemd
In the same file, enable jails you want to configure. In this config example, jump to ssh server jail ([sshd] section) and write:
[sshd] # sshd section in jail.conf
enabled = true
Enable fail2ban service with systemctl utility:
systemctl enable fail2ban
If you have enabled one or more jails, in fail2ban logs, maybe you should read this error message:
fail2ban-client[11363]: ERROR NOK: ("Failed to initialize any backend for Jail 'sshd'",)
fail2ban-client[11363]: ERROR NOK: ('sshd',)
To resolve this issue you make sure that you've installed python-systemd rpm.