A Mechanism to Migrate Linux Processes onto FreeBSD Toward Dynamically OS Switching

Abstract

In the process of technological progress of the computer, research and development of the operating system (OS), which is the primary software, has been actively carried out, and several OS implementations have become available in use. Although a few operating systems, such as Windows and Linux, are in an oligopoly for some platforms, such as desktop PCs, smartphones, and enterprise servers, no one OS has a monopoly for all systems. Even today, each of the existing multiple OSes is selectively used in different ways, depending on the purpose and platform characteristics of the target system. The authors propose a method to improve the load tolerance and performance of services running on an OS by dynamically switching between multiple OSes with different characteristics according to the changing situation. In this paper, we summarize the implementation of a Linux-compatible migration mechanism for Linux and FreeBSD to enable the dynamic switching of the operating system on the system's infrastructure during the service operation. By maintaining the mutual compatibility of checkpoint data with CRIU, the standard tool for process migration mechanism in Linux, we implement a mechanism for migration of the same process between Linux and FreeBSD. This article focuses not only on the differences between the functions of the FreeBSD and Linux kernels but also on the differences in their internal structures and interface specifications. It explains the challenges and techniques for implementing the same functions as those of the CRIU tool on FreeBSD.