1. A method for flexible network load balancing, the method comprising: operating network load balancing infrastructure in a first configuration that includes forwarding functionality, classifying functionality, and session tracking functionality at a first resource distribution allocation; the first resource distribution allocation to allocate first, second, and third percentages of load balancing resources to the forwarding functionality, the classifying functionality, and the session tracking functionality, respectively; wherein the first configuration comprises, at least in part, a device that executes host functionality; scaling out the network load balancing infrastructure by adjusting from the first configuration at the first resource distribution allocation to a second configuration at a second resource distribution allocation; and operating the scaled-out network load balancing infrastructure in the second configuration that includes the forwarding functionality, the classifying functionality, and the session tracking functionality at the second resource distribution allocation; the second resource distribution allocation to allocate fourth, fifth, and sixth percentages of the load balancing resources to the forwarding functionality, the classifying functionality, and the session tracking functionality, respectively; wherein the second configuration comprises, at least in part, another device that does not execute host functionality; wherein: the scaling out comprises moving at least a portion of network-load-balancing functionality from the device that executes host functionality to the other device, that does not execute host functionality; the operating network load balancing infrastructure comprises routing network traffic internally within the device to the host functionality executing thereon; and the operating the scaled-out network load balancing infrastructure comprises routing network traffic from the other device to the host functionality executing on the device.