Monday, January 20, 2014

Unikernels: Rise of the Virtual Library Operating System

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Cloud computing has been pioneering the business of renting computing resources in large data centers to multiple (and possibly competing) tenants. The basic enabling technology for the cloud is operating-system virtualization such as Xen1 or VMWare, which allows customers to multiplex VMs (virtual machines) on a shared cluster of physical machines. Each VM presents as a self-contained computer, booting a standard operating-system kernel and running unmodified applications just as if it were executing on a physical machine.

A key driver of the growth of cloud computing in the early days was server consolidation. Existing applications were often installed on physical hosts that were individually underutilized, and virtualization made it feasible to pack them onto fewer hosts without requiring any modifications or code recompilation. VMs are also managed via software APIs rather than physical actions.

They can be centrally backed up and migrated across different physical hosts without interrupting service. Today commercial providers such as Amazon and Rackspace maintain vast data centers that host millions of VMs. These cloud providers relieve their customers of the burden of managing data centers and achieve economies of scale, thereby lowering costs.

While operating-system virtualization is undeniably useful, it adds yet another layer to an already highly layered software stack now including: support for old physical protocols (e.g., disk standards developed in the 1980s, such as IDE); irrelevant optimizations (e.g., disk elevator algorithms on SSD drives); backward-compatible interfaces (e.g., POSIX); user-space processes and threads (in addition to VMs on a hypervisor); and managed-code runtimes (e.g., OCaml, .NET, or Java). All of these layers sit beneath the application code. Are we really doomed to adding new layers of indirection and abstraction every few years, leaving future generations of programmers to become virtual archaeologists as they dig through hundreds of layers of software emulation to debug even the simplest applications?

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One Response so far.

vimal parekh said...

Really a nice stuff. actually such type of things are happening in other Operating system also. such stuff also available on All Android Answers

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