AWStuff: Dedicated Instance vs. Dedicated Host

Introduction

Hello everyone,

Today, I will try to summarize a bit complicated concept in easiest possible terms.

The concept is in the domain of EC2 (Elastic Compute Cloud) which is most widely used service in AWS. This service allows you to rent your own computer in the cloud where you can run windows, linux or any other OS.

But it has different types and flavors as well.

One of the concept that confuses us is between dedicated instance vs. dedicated host in EC2.

So, let's explore that!

Video Explanation

Dedicated Instance Vs. Dedicated Host

Lets begin with the official documentation:

Dedicated Instance

By default, EC2 instances run on shared tenancy hardware. This means that multiple AWS accounts might share the same physical hardware.
Dedicated Instances are EC2 instances that run on hardware that's dedicated to a single AWS account. This means that Dedicated Instances are physically isolated at the host hardware level from instances that belong to other AWS accounts, even if those accounts are linked to a single payer account. However, Dedicated Instances might share hardware with other instances from the same AWS account that are not Dedicated Instances.

Source: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/dedicated-instance.html

Dedicated Host

Amazon EC2 Dedicated Hosts allow you to use your eligible software licenses from vendors such as Microsoft and Oracle on Amazon EC2, so that you get the flexibility and cost effectiveness of using your own licenses, but with the resiliency, simplicity and elasticity of AWS. An Amazon EC2 Dedicated Host is a physical server fully dedicated for your use, so you can help address corporate compliance requirements.

Source: https://aws.amazon.com/ec2/dedicated-hosts/

Difference?

From the docs, they both look like something similar, right?

But that is not the case.

Let me try and explain it...

So, in general, whenever you go for EC2 instance, AWS will give you any hardware where your instance will be deployed and then you can use OS (Windows/Linux). You do not get the control over hardware at all. Note that the hardware is very huge like CPU, RAM and other stuff so it will be shared with other instances as well.

When you choose to go for Dedicated Instance then you get your instance dedicated on one hardware which is not currently occupied by any one else.

Every time you stop and start your instance, you will not be given the same hardware but you will be given an isolated hardware to your own AWS account.

When you choose to go for Dedicated Host, you lock down for a particular hardware where you can deploy your instances.

Whenever you stop and start your instance, you will get same hardware for your instances.

Conclusion

In this article, I tried to explain the difference in easiest terms in AWS EC2 for dedicated host and dedicated instance.

In dedicated instance, you get isolated to one hardware but every time you stop/start the instance then you get a different hardware but in dedicated instance, you get same hardware after you stop and start the instance.

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