A good example is Cisco, which killed off its Application Control Engine (ACE) production line and instead redirected customers to a virtual ADC product that it developed with Citrix, the Netscaler 1000v. Meanwhile, Brocade launched a virtual ADX load balancer earlier this year, thanks in no small part to the expertise it acquired from the Vyatta acquisition.
What's the appeal of a virtual ADC? A virtualized appliance doesn't need complicated hardware drivers. It can also run just as fast as the processor underneath, eliminating issues with hardware upgrades or module incompatibility. Some ADC vendors enable virtual ADCs on their physical appliances, which lets customers implement a greater degree of segmentation, such as in multitenant environments. Virtual ADCs can also be deployed on standard x86 servers, which are typically less expensive than purpose-built load balancing hardware.
It's possible that the next phase of development is to integrate a load balancer into the VM itself. That would remove the need for dedicated hardware and allow the vCPU to take over processing duties for balancing the traffic. The host-based ADC would have much better visibility over the incoming traffic load and would negate the need for having a very large piece of hardware (or significant server cluster) sitting in front of the server farm to balance traffic that may only be going to a subset of the systems sitting behind it.
[The startup Embrane is marrying virtual appliances and SDN. Ethan Banks gives his take on it in "SDN Startup Creates Distributed Virtual Appliances."]
Of course, some people aren't keen on the idea of NFV for everything. A 1U hardware appliance with blinking lights is a comfort to some admins. In addition, issues with the hypervisor could negatively affect performance of any virtualized units. Proper planning and implantation are essential for any virtualized system, and they become even more important when the system being virtualized acts as a gateway to hundreds of other virtual systems.
Care must also be taken when upgrading the underlying hypervisor software. Incompatibility with a firmware upgrade on a hardware device can be easily solved by not upgrading. However, if the hypervisor must be upgraded to support a critical server feature but risks breaking NFV appliances, the upgrade decision becomes much more complicated.
Virtualizing ADCs and load balancers seems to be the wave of the future, but what does that mean for vendors such as F5, which can command premium prices for its hardware? And what does it mean for IT organizations that are comfortable with the hardware appliance model? Are you ready to embrace an NFV future, or do you see a role for hardware in the ADC market? Be sure to leave a comment and let me know what you think.