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Programmable IO across Virtual and Physical Infrastructures

By August 11, 2015October 19th, 2016Blog

In recent years, with the advent of virtualization, private and public clouds, the nature of application development and deployment has changed significantly. The demands on today’s businesses require applications to be deployed at scale in minutes, and not days, months or years. The need for agility and scale extends to the infrastructure functions needed to support these applications, like networking, storage, security and load balancing.

The advent of software defined functions, like Software-defined Networking (SDN) and Software-defined Storage (SDS), and Software-defined Security (SD-Sec), attempt to deliver on the promise of just-in-time provisioning, auto-scaling and fine grained policy control. A logical way to scale some of these IO functions is to allow them to be implemented in the host OS stack.

The IO Visor project attempts to add the ability to programmatically insert IO functions into the data plane of the Linux kernel to allow for software defined control of infrastructure needed to support modern day applications.  IO Visor requires that clearly specified data plane functions be compiled into a format that can be inserted into data plane of the Linux kernel.

Barefoot Networks has contributed to the development of P4, an open, domain specific language, that is designed to specify and program networking data planes. P4 is an imperative language that allows one to describe the data plane behavior in an intuitive manner.

P4 is the perfect high-level language to specify IO functions in IO Visor. P4 allows for concise, unambiguous, and human readable specification of IO behavior, especially when compared to alternate forms of specification using procedural languages like C. IO functions specified in P4 can be compiled into the extended Berkeley Packet Filter (eBPF) format and pushed into the data plane of the Linux kernel.

Barefoot Networks has prototyped a compiler that compiles P4 programs into LLVM IR. This LLVM IR is further compiled into eBPF using the LLVM compiler. We will contribute this compiler and the supporting tool chain to the IO Visor project by open sourcing the implementation under a permissive license. We believe that this contribution will significantly accelerate the specification of IO functions in the IO Visor project.

We look forward to a world where IO functions can be programmed easily and quickly on both virtual and physical networking infrastructures to adapt to the needs of the applications.

About the author of this post

ck-imageChaitanya (CK) Kodeboyina