Bare Metal – By Meaning
Bare metal is computer hardware that runs without an operating system.
Bare machine (or bare metal), in computer parlance, means a computer without its operating system. Modern operating systems evolved through various stages, from elementary to the present day complex, highly sensitive real-time systems. After the development of programmable computers (which did not require physical changes to run different programs) but prior to the development of operating systems, programs were fed to the computer system directly using machine language by the programmers without any system software support. This approach is termed the “bare machine” approach in the development of operating systems. Today it is mostly applicable to embedded systems and firmware, while everyday programs are run by a run-time system within an operating system.
Bare Metal – As understood Today
A new computer system that does not contain an operating system or any software. For example, when you purchase a new hard drive it is completely empty, or “nothing but bare metal”.
A bare metal environment is a computer system or network in which a virtual machine is installed directly on hardware rather than within the host operating system (OS). The term “bare metal” refers to a hard disk, the usual medium on which a computer’s OS is installed.
With the “cloudification” of IT, new terms have appeared across the hosting industry. One among the most popular terms is bare metal. To answer simply, a bare-metal server is our traditional dedicated server with a hip new name for the cloud generation!
Bare metal is a single tenant server. This means only you are taking the resources of the server. The server belongs to you and you only. Compared to the cloud model where multiple users (multi-tenancy) reside on the same physical server, the bare-metal server only has one customer on the server.
Single tenancy allows you to avoid the noisy neighbor effect, which is described as a user impacting the performance and stability of other users within the same server. With bare metal, since you are the sole user, you will not witness the noisy neighbor effect.
Bare metal supports multiple types of operating systems on top of it, including hypervisors. This brings us to our next point – the difference between bare metal and hypervisors.
What is a hypervisor and how does it differ from bare metal? A hypervisor is an operating system that can create virtual machines (VM) within a bare-metal server. Let’s have a look at the representation below to better understand the difference between the two.
Bare-metal server without hypervisor Bare-metal server with hypervisor
The first image above represents a traditional bare-metal server. The operating system (CentOS, Debian, Redhat, SUSE, Ubuntu, Windows Server, etc.) is installed directly on the server, and applications are running natively in the operating system.
In the second image above, a bare-metal server installed with a hypervisor provides the user with a management suite to create virtual machines on the server. The hypervisor should not run applications natively; rather, its purpose is to virtualize your workloads into separate virtual machines to gain the flexibility and reliability of virtualization.