JeOS (just enough operating system)

JeOS (just enough operating system) is a customized operating system built for a virtual appliance.

JeOS (just enough operating system)

Just Enough Operating System (JeOS, pronounced "juice") is a paradigm for customizing operating systems to fit the needs of a particular application such as for a software appliance. The platform only includes the operating system components required to support a particular application and any other third-party components contained in the appliance, (e.g., the kernel). This makes the appliance smaller, faster (to boot and to execute the particular application) and potentially more secure than an application running under a full general-purpose OS.

JeOS (just enough operating system) is a highly customized operating system built for a specific application. The acronym is pronounced "juice."

JeOS builds are popular with software vendors and developers who are creating test systems or virtual appliances.  A virtual appliance is simply a virtual machine (VM) image file that has a preconfigured operating system (OS) and a single application. (The preconfigured OS is the JeOS.) 

A JeOS only includes the bits of a full-blown operating system that are required to support the application and any other third-party components that are packaged in the appliance.  Configuring the JeOS and the application together in a single package helps avoid installation issues and errors.

Typically, a JeOS will consist of the following:

  • JeOS media (OS core {kernel, virtual drives, login})
  • OS minimum maintenance tools
  • Minimum user space tools
  • Packages repository (DVD or network based)

It is important to differentiate between true fully minimalized OS install profiles forced, for example, with security hardening tools or representing Recovery Console images and JeOS richer install profiles which are designed and built for wider audience usage, so VM/VA creators and their users can easily perform needed installation or configuration tasks.