systemd - define a service without ExecStop and be able to stop it without "fail"

I am with CentOS 7, and I want to start Kafka standalone producer (File Connector) as a service. The command is: /opt/kafka/bin/connect-standalone.sh /opt/kafka/config/connect-standalone.properties /opt/kafka/config/connect-file-source.properties And, obviously, it has no stop command. Normally, I just Ctrl+C to stop it as a foreground process. But when I test, I found very tedious to open several terminal console session to run several processes (Zookeeper, Kafka server, Kafka producer, Storm jar, etc.) so I change Zookeeper and Kafka server as service, which have their stop script. But in this case, no. I tried systemctl start kafka-producer and systemctl stop kafka-producer, but the service entered failed status, and is not stopped. I had to delete the service, reload the daemon, and switch to manual again. kafka-producer.service: [Unit] Description=Kafka Producer After=network.target [Service] Type=simple ExecStart=/opt/kafka/bin/connect-standalone.sh /opt/kafka/config/connect-standalone.properties /opt/kafka/config/connect-file-source.properties Restart=on-abort [Install] WantedBy=default.target Anyway to manipulate a service without ExecStop command?