Have you ever wondered what it would be like to have everything in the world just for yourself — where every resource and every service is just for you? Imagine you have rented a private villa on a small, quiet island. Everything in the villa — the rooms, the pool, and the beach — is just for you. No other guests can use anything there, and the staff are there just for you. Isn’t that exciting? I’m sure it is!
This concept also applies to applications, which are given their own space to work in without interference from others and without sharing resources. Any application could thrive in such an environment. So, the question is: “Does such an application environment exist?”
Enter unikernels — a unique application environment that can provide an exclusive environment just like your private villa. They are compact, single-application virtual machines, boosting speed, efficiency, and security.
In this article, we will take a closer look at what unikernels are, explore the different types of unikernels, discuss their benefits and limitations, and learn how to create and deploy a simple Nanos application (a type of unikernel) on AWS.
What is a Unikernel and why do we need it?
Before we look at unikernels, let us first understand why we need something like unikernels in the first place, and examine the limitations of current operating systems like Linux and Windows that lead us to look for alternatives.
Traditional operating systems are designed to run multiple applications simultaneously, which requires careful resource management to ensure smooth operation. The operating system kernel also performs numerous background tasks via memory management, process scheduling, disk I/O and peripheral management. However, our backend applications often do not need these functions, and yet the kernel consumes a lot of memory and CPU power to support them.
The solution to the above problem is simple: if the operating system causes too much overhead, why not let the user-space program take control of the hardware directly? This way, the application essentially becomes part of the kernel, accesses the hardware with fewer obstacles and significantly reduces the overhead of the operating system.
This is exactly the goal of unikernels — fine-tuning for specific tasks. They are lightweight, specialized virtual machines designed to run a single application, making the system smaller, faster and more secure. This unique form of virtualization merges the application and operating system into a single executable image, eliminating the need for the extensive features and services of traditional operating systems.
This specialization makes the system simpler and reduces resource consumption. It only contains the essential components required for the respective application and is, therefore, much smaller than conventional operating systems. This lean design leads to faster boot times and lower memory consumption. In addition, the smaller attack surface of unikernels also improves security.
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