Virtual Open Systems Scientific Publications

Introduction

Virtualization has been developed as a mature technology over the years in the cloud based environment to help in providing an efficient way to make use of the available computing resources and improve the quality of services. Recently, it has appeared as a vital component in the upbringing of new networking solutions like Software Defined Networking (SDN) and Network Functions Virtualization (NFV). Current Network Operators’ networks are comprised of diverse network functions and variety of proprietary hardware appliances. Often, launching a new network service requires new complicated hardware design coupled with the cost of space and energy demands for installation.

NFV tries to address these issues by making use of standard virtualization technologies to decouple network hardware from the software implementation of network functions for faster network service provisioning. NFV implements these network functions as Virtual Network Functions (VNFs) in software which can be run on a large range of standard industry servers and can be ported or instantiated easily on different locations without the need to install specialized hardware equipments at every site.

In order to keep up with the demands of the market, virtualization technologies like hypervisors have been making major development improvements equally for both x86 and ARM architectures as they have introduced hardware extensions to support virtualization. However, VMs have not proved to be as efficient in specific use cases where smooth scaling and density of applications comes into play. These shortcomings are mostly due to the large size of the guest OS which waste a huge amount of system resources. To overcome this, new virtualization techniques such as container-based virtualization and unikernels have emerged as efficient lightweight alternatives to traditional VMs for specific cases of small or medium size application deployments.

Containers in contrary to VMs, avoid deploying a full blown copy of an operating system (OS) for each instance and instead depend on sharing the same base OS among themselves. Every application running inside a container is provided with the required set of binaries and libraries to support its execution. Unikernels focus on the idea of reducing the size of the traditional VMs by eliminating the unnecessary components and are built by combining only the specialized application image and OS software parts that are needed to make it run as intended.

Containers and unikernels both benefit from their small sizes by providing faster boot times, reduced attack surface, smaller resource footprints and room for optimization. Figure 1 focuses on highlighting these architectural differences among the three technologies.

In this paper we compare the performance of hypervisors, containers and unikernels on the x86 and ARMv8 architectures. However, unikernels benckmarks do not appear in the ARMv8 results because they are not yet mature enough on this architecture. The hypervisor we selected is the well known solution KVM, the container engines we chose are Docker and rkt and finally we have Rumprun and OSv as our unikernel candidates. This study focuses on how these solutions compare to each other in terms of system and network I/O specific metrics which prove vital in context of NFV.