This behavior also somewhat contradicts the principles of building cloud-computing environments, since network performance issues can inhibit the ability to deliver the any-service-anywhere we expect from true cloud deployments. The same can be said about maintaining security policy and segmentation between cloud tenants or accelerating client-server application traffic throughout virtual server mobility events.
It is clear that a new concept in infrastructure service delivery needs to be created, but do we really need to completely "reinvent the wheel"?
Not necessarily. We all have grown to trust the virtual switching currently happening in the Hypervisor Layer. We also know that having virtual machine mobility does not impair our ability to carry its network connectivity properties, such as for example VLAN assignment, from source to destination physical server. This is seamlessly done by the distributed virtual switch, which is either embedded in the hypervisor or installed on top of it.
Now, what if we could make our stateful service appliances behave in the similar way by "following" the virtual machine as it moves around, rather than staying still and expecting virtual machine or, more precisely, the network in between, to deliver the traffic in a "fan-out" fashion?
This is exactly what conceptually happens with virtualized service appliances. Technically, traffic still gets forwarded from the virtual servers to the virtual service appliances, however all of this is seamlessly done on the hypervisor level by the virtual service appliances themselves, once they have been set up. The outside data center fabric is no longer tasked with keeping traffic symmetry, security segmentation and policy enforcement or application acceleration. Sweet.
Virtual service appliances run on top of the hypervisor and work in tandem with distributed virtual switches to make sure that services are applied to the virtual machine wherever it goes in consistent fashion.
As cloud computing is gaining more traction in the service provider and enterprise space, so does the evolution of virtual service appliances and hypervisor delivered services. Some are still skeptical about how well do those platforms perform compared to hardware appliances and although such concerns are not entirely unsubstantiated, the advantages of flexibility and adaptability cannot be underestimated. Keep your eyes open for things to come.
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