Managing individual cluster units in a virtual cluster

Managing individual cluster units in a virtual cluster

You can select the HA option Do NOT Synchronize Management VDOM Configuration if you have enabled multiple VDOMS and set a VDOM other than the root VDOM to be the management VDOM. You can select this option to prevent the management VDOM configuration from being synchronized between cluster units in a virtual cluster. This allows you to add an interface to the VDOM in each cluster unit and then to give the interfaces different IP addresses in each cluster unit, allowing you to manage each cluster unit separately.

You can also enable this feature using the following command:

config system ha

set standalone-mgmt-vdom enable end

This feature must be disabled to manage a cluster using FortiManager.


The primary unit acts as a router for subordinate unit management traffic

HA uses routing and inter-VDOM links to route subordinate unit management traffic through the primary unit to the network. Similar to a standalone FortiGate unit, subordinate units may generate their own management traffic, including:

  • DNS queries.
  • FortiGuard Web Filtering rating requests.
  • Log messages to be sent to a FortiAnalyzer unit, to a syslog server, or to the FortiGuard Analysis and Management Service.
  • Log file uploads to a FortiAnalyzer unit.
  • Quarantine file uploads to a FortiAnalyzer unit.
  • SNMP traps.
  • Communication with remote authentication servers (RADIUS, LDAP, TACACS+ and so on)

Subordinate units send this management traffic over the HA heartbeat link to the primary unit. The primary unit forwards the management traffic to its destination. The primary unit also routes replies back to the subordinate unit in the same way.

HA uses a hidden VDOM called vsys_ha for HA operations. The vsys_ha VDOM includes the HA heartbeat interfaces, and all communication over the HA heartbeat link goes through the vsys_ha VDOM. To provide communication from a subordinate unit to the network, HA adds hidden inter-VDOM links between the primary unit management VDOM and the primary unit vsys_ha VDOM. By default, root is the management VDOM.

Management traffic from the subordinate unit originates in the subordinate unit vsys_ha VDOM. The vsys_ha VDOM routes the management traffic over the HA heartbeat link to the primary unit vsys_ha VDOM. This management traffic is then routed to the primary unit management VDOM and from there out onto the network.

DNS queries and FortiGuard Web Filtering and Email Filter requests are still handled by the HA proxy so the primary unit and subordinate units share the same DNS query cache and the same FortiGuard Web Filtering and Email Filter cache. In a virtual clustering configuration, the cluster unit that is the primary unit for the management virtual domain maintains the FortiGuard Web Filtering, Email Filtering, and DNS query cache.


Subordinate unit management traffic path


Cluster communication with RADIUS and LDAP servers

In an active-passive cluster, only the primary unit processes traffic, so the primary unit communicates with RADIUS or LDAP servers. In a cluster that is operating in active-active mode, subordinate units send RADIUS and LDAP requests to the primary unit over the HA heartbeat link and the primary units routes them to their destination. The primary unit relays the responses back to the subordinate unit.

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About Mike

Michael Pruett, CISSP has a wide range of cyber-security and network engineering expertise. The plethora of vendors that resell hardware but have zero engineering knowledge resulting in the wrong hardware or configuration being deployed is a major pet peeve of Michael's. This site was started in an effort to spread information while providing the option of quality consulting services at a much lower price than Fortinet Professional Services. Owns PacketLlama.Com (Fortinet Hardware Sales) and Office Of The CISO, LLC (Cybersecurity consulting firm).

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