systemd service update:

- starting service in normal mode (without forking)
- does not restart if service exited normally (exit-code 0, e.g. stopped via fail2ban-client)
- does not restart if service can not start (exit-code 255, e.g. wrong configuration, etc.)
- service can be additionally started/stopped with commands (fail2ban-client, fail2ban-server)

files/fail2ban.service

@@ -5,12 +5,13 @@ After=network.target iptables.service firewalld.service
 PartOf=iptables.service firewalld.service
 
 [Service]
-Type=forking
-ExecStart=/usr/bin/fail2ban-client -x start
+Type=simple
+ExecStart=/usr/bin/fail2ban-server -xf start
 ExecStop=/usr/bin/fail2ban-client stop
 ExecReload=/usr/bin/fail2ban-client reload
 PIDFile=/var/run/fail2ban/fail2ban.pid
-Restart=always
+Restart=on-failure
+RestartPreventExitStatus=0 255
 
 [Install]
 WantedBy=multi-user.target