Cluster operation

Cluster operation defines how multiple FortiGate units function together as a cohesive High Availability (HA) system using the FortiGate Clustering Protocol (FGCP). This operational framework governs how cluster members communicate, negotiate roles (Primary versus Secondary), and manage network traffic.

Key aspects of cluster operation include:

• Operating Modes: Defining whether standby units are passive or actively processing traffic.

• Traffic Management: utilizing load balancing schedules to distribute specific security tasks.

• Virtualization: Segmentation of the cluster into virtual clusters for granular VDOM control.

• Election Logic: The deterministic criteria used to select the primary unit during startup or failover events.

The following sections provide detailed configuration guidelines and behavioral insights for these components:

Topic	Summary
HA primary unit selection criteria	The strict logic and hierarchy the FortiGate uses to deterministically elect a Primary unit during startup or recovery.
HA active-passive cluster setup	The standard redundancy model where one unit handles all traffic while the other remains in standby, ready to take over instantly if the primary fails
HA active-active cluster setup	A performance-oriented configuration where both units actively process traffic, allowing you to leverage the resources of the secondary unit for specific security tasks.
Single FortiGuard license for FortiGate A-P HA cluster	Specific configuration details for sharing a single service license across cluster units using a Virtual Serial Number (vSN) on supported models.
HA virtual cluster setup	An advanced strategy using Virtual Domains (VDOMs) that allows different units to act as the Primary for different logical network segments, maximizing hardware utilization without the complexity of full Active-Active mode.