From Nagios Support Wiki
Official information on Nagios Fusion can be found here.
Nagios Fusion provides organizations with the ability to quickly identify and solve problems on an infrastructure-wide basis before they affect critical business processes. IT operations staff use Nagios Fusion to gain insight into in the health of the organization's entire network through a centralized view of their monitoring infrastructure. Tactical overview screens display the status of hosts and services monitored by all Nagios Core and Nagios XI servers deployed throughout the organization, enabling faster problem detection and resolution.
Find out more about Fusions's capabilities by visiting the product information link:
Video tutorials that guide you through various aspects of Fusion usage and concepts.
Individual documents that explain various aspects of administering and using Nagios Fusion.
Answers to Frequently Asked Questions about Nagios Fusion.
Other Support Resources
Support for Nagios Fusion is provided via our online support forum at the link below.