Citrix Blends OpenFlow & Cloud
At next week's Open Networking Summit, in Santa Clara, Calif., the company will show its open-source management platform, CloudStack, helping to provision virtual machines in conjunction with a variety of SDN controllers.
The concept is aimed at the providers doing infrastructure as a service (Iaas), because there's evidence that IaaS and cloud are going to go hand-in-hand, says Chiradeep Vittal, a software architect for Citrix.
"We believe Amazon Web Services has set the standard. CloudStack is trying to emulate the AWS example," he says.
Core to that idea is the belief that AWS uses one application programming interface (API) to tell the network and the cloud how to provision a virtual machine. That is, when a new job starts running in the cloud, you don't need to issue separate commands to tell the switches and the storage elements what to do.
The point of the demo is to show CloudStack handling all that orchestration.
Citrix will be emphasizing the open-source nature of CloudStack, and of many of the demo elements themselves. But the company is using the demo less as a product advertisement than as a launching point for discussion, to hear Vittal tell it. "We are not asserting this is the way to go. This is one way to go, and we're looking for feedback at the Summit," he says.
Specifically, there are other ways to build the overlay networks -- the alternative switching rules -- that SDN would dictate to the network's switches. Citrix happens to be building those overlays by using generic route encapsulation (GRE) tunnels. Other possibilities include VXLAN and NVGRE, both of which have been submitted to the IETF for standardization. Because hypervisors don't support any of those options yet, Citrix went with a vanilla GRE implementation, Vittal says.
(Cisco Systems Inc. (Nasdaq: CSCO), Citrix, VMware Inc. (NYSE: VMW) and others are on the VXLAN side, while NVGRE, which is based on GRE tunnels, came from Microsoft Corp. (Nasdaq: MSFT), Dell Technologies (Nasdaq: DELL) and others. Interestingly, Arista Networks Inc. helped write both proposals.)
An even simpler way to do those overlay networks would be with virtual LANs (VLANs) -- but they typically won't be the answer because the network is limited to about 4,000 of them. Vittal, for one, is convinced Amazon doesn't use virtual LANs in its cloud. (He points out that Amazon doesn't disclose exactly how its cloud works, but he's convinced the company is using SDN widely.)
— Craig Matsumoto, Managing Editor, Light Reading