When you try to connect to the web application you get a “The Connection was reset” in Firefox or “The page isn’t working” in Chrome.
Check if OpenNMS daemons are running with
root@localhost:~# opennms -v status OpenNMS.Eventd : running OpenNMS.Alarmd : running OpenNMS.Bsmd : running OpenNMS.Ticketer : running OpenNMS.Trapd : running OpenNMS.Queued : running OpenNMS.Actiond : running OpenNMS.Notifd : running OpenNMS.Scriptd : running OpenNMS.Rtcd : running OpenNMS.Pollerd : running OpenNMS.PollerBackEnd : running OpenNMS.EnhancedLinkd : running OpenNMS.Collectd : running OpenNMS.Discovery : running OpenNMS.Vacuumd : running OpenNMS.EventTranslator: running OpenNMS.PassiveStatusd : running OpenNMS.Statsd : running OpenNMS.Provisiond : running OpenNMS.Reportd : running OpenNMS.Ackd : running OpenNMS.JettyServer : running OpenNMS.Telemetryd : running opennms is running
The important daemon JettyServer is responsible serving the web application. When all services are up and running. Check if the port is open and in state “LISTEN” with:
root@localhost:~# ss -lnpt sport = :8980 State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 50 :::8980 :::* users:(("java",pid=61160,fd=902))
Check if you have a firewall running:
systemctl status firewall
See which services are allowed on CentOS with firewalld with
root@localhost:~# firewall-cmd --list-services
The service is running but it is not possible to connect to the service.
Add a rule to your default zone which allows incoming TCP connections to the OpenNMS Web application on port 8980 and restart firewalld.
root@localhost:~# firewall-cmd --permanent --add-port=8980/tcp success root@localhost:~# systemctl restart firewalld