/etc/systemd/system/jenkins-agent.service

[Unit]
Description=Jenkins agent

[Service]
Type=simple
ExecStart=/usr/bin/java -jar /root/agent.jar -url <URL> -secret <SECRET> -name <HOST_NAME> -workDir /home/jenkins -webSocket
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

Reload systemd and restart the service

systemctl daemon-reexec

systemctl daemon-reload

systemctl restart jenkins-agent

Watch logs live

journalctl -u jenkins-agent -f