A floating IP is a virtual IP address used for routing outgoing traffic from a load balancer’s output interface to the backends. It “floats” between nodes in a cluster, ensuring seamless service continuity.

In simpler terms, a floating IP leverages virtual interfaces to masquerade outbound traffic, regardless of whether it traverses a NIC, VLAN, or Bonding interface on both cluster nodes. When the cluster changes its master role, services (e.g., Farms) associated with a floating IP seamlessly switch from one node to another. This transition occurs transparently without impacting clients, backend connections, or data streams.

Imagine an application load balanced across servers A and B. Server A receives traffic via the load balancer’s output IP (the floated IP). If the MASTER load balancer experiences downtime or technical issues, ongoing traffic between the floated IP and the backend IP continues without interruption. The load balancer’s cluster service automatically moves the service to the other node while maintaining traffic flow using the same floating IP. This allows the load balancer’s connection tracking system to smoothly manage traffic, ensuring no downtime is noticed by the backends.

In business environments where downtime can lead to substantial financial losses, ensuring continuous server uptime to process client requests is critical.

Floating IPs Table #

Descriptions of the Fields:
Interface. Name of the parent interface (e.g., VLAN, bonding, or NIC).
Interface IP. IP address of the parent interface.
Interface alias. Memorable name identifying the parent interface.
Interface Virtual. Name of the virtual interface from which the floating IP is selected.
Floating IP. Configured IP address inherited from the virtual interfaces.
Actions. Actions for managing floating IPs.

• Configure. Assign a floating IP address to the parent interface. Only one floating IP can be assigned.
• Unset. Clear the configuration and remove the virtual IP address.