Stop OpenNMS Horizon service
sudo systemctl stop opennms
Back up OpenNMS Horizon binaries, RRD archives, configurations
sudo tar --exclude='/opt/opennms/data/cache' -cvzf /tmp/opennms-opt.tar.gz /opt/opennms && \
sudo tar -cvzf /tmp/opennms-var.tar.gz /var/opennms
Create PostgreSQL database backup
sudo runuser -l postgres -c 'pg_dumpall -f /tmp/opennms-postgres.dmp'
Back up OpenNMS Horizon operating system user
sudo grep opennms /etc/passwd > /tmp/opennms-passwd.txt && \
sudo grep opennms /etc/group > /tmp/opennms-group.txt