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.