Configure PostgreSQL database access
sudo vi /usr/share/opennms/etc/opennms-datasources.xml
Set credentials to access the PostgreSQL database
<jdbc-data-source name="opennms"
                    database-name="opennms"(1)
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/opennms"
                    user-name="** YOUR-OPENNMS-USERNAME **"(2)
                    password="** YOUR-OPENNMS-PASSWORD **" />(3)

<jdbc-data-source name="opennms-admin"
                    database-name="template1"
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/template1"
                    user-name="postgres"(4)
                    password="** YOUR-POSTGRES-PASSWORD **" />(5)
1 Set the database name Horizon should use.
2 Set the user name to access the opennms database table.
3 Set the password to access the opennms database table.
4 Set the postgres user for administrative access to PostgreSQL.
5 Set the password for administrative access to PostgreSQL.
Detect Java environment and persist in /usr/share/opennms/etc/java.conf
sudo /usr/share/opennms/bin/runjava -s
Initialize the database and detect system libraries persisted in /opt/opennms/etc/libraries.properties
sudo /usr/share/opennms/bin/install -dis
Enable Horizon core instance on system boot and start immediately
sudo systemctl enable --now opennms
By default the OpenNMS SNMP Trap daemon listens on 162/udp and the Syslog daemon listens on 10514/udp. The SNMP Trap daemon is enabled by default, the OpenNMS Syslog daemon is disabled.