Configure Horizon components to use your existing ActiveMQ instance. Create a properties file for the ActiveMQ settings sudo vi etc/opennms.properties.d/activemq.properties Disable embedded ActiveMQ and set the credentials for your ActiveMQ endpoints org.opennms.activemq.broker.disable=true(1) org.opennms.activemq.broker.url=failover:tcp://my-activemq:61616(2) org.opennms.activemq.broker.username=my-activemq-user(3) org.opennms.activemq.broker.password=my-activemq-password(4) org.opennms.activemq.client.max-connections=8(5) org.opennms.activemq.client.concurrent-consumers=10(6) 1 Disable embedded ActiveMQ in Horizon Core instance. 2 Set the URL endpoint to your dedicated ActiveMQ instance. Replace my-active-mq:61616 accordingly. If you use ActiveMQ with SSL, replace tcp with ssl. 3 Set a user name for ActiveMQ authentication. 4 Set the password for ActiveMQ authentication. 5 By default we allow a maximum of 8 connections. Increase it depending on your size. 6 By default we allow a maximum of 10 concurrent consumers. Increase it depending on your size. Restart Horizon Core instance to apply the changes sudo systemctl restart opennms