[Introduction] Getting started with Amazon EC2 Reserved Instances

nice to meet you.
I am an infrastructure manager in the system solution department.

Since joining Beyond in September, I have been involved in a variety of tasks, and I am getting more fulfilled every day.

Now, this time we will talk about the AWS instance "Amazon EC2".

Introduction

I would like to briefly write about the costs that everyone always considers when using AWS EC2 instances

When creating an EC2 instance, you probably use an on-demand instance with pay-as-you-go pricing

However, when I was researching the pricing structure of AWS instances, I came across sentences like this.

Amazon EC2 Reserved Instances (RI) allow you to reserve capacity for use in a specific Availability Zone at a significant discount (up to 72%) compared to On-Demand pricing.

Source: AWS https://aws.amazon.com/jp/ec2/pricing/reserved-instances/

Up to 72% off! ? Seriously! ?

Reserved Instances
provided by AWS is a very profitable system as mentioned above if the conditions are met

However, it's a pain to read and understand the documentation, and even though I read it, I still don't really understand it! That tends to be the case. (That's what happened to me in the beginning)

As you can see, Reserved Instances are a bit difficult to approach, but I happened to come across them at work, so like myself, I had never touched them before! I would like to summarize this with the explanation for beginners.

Please note that Reserved Instances can be used with other services such as Amazon RDS, but this article will focus on EC2 Reserved Instances as an introductory guide, so please keep that in mind.

What is a Reserved Instance?

First of all, what is a Reserved Instance? In short, it is an instance commuter pass .

In short, if you buy one year's worth (or three years' worth) in bulk, I'll give you a cheaper price! This is the system.

Please note that this is a good deal if you keep your instances running all the time, but it is a waste if you frequently stop your instances.

Isn't it a waste to buy a commuter pass if you only ride the train once in a while?

So, be sure to check how you will operate the instance before introducing it!

In addition, there are many features that you should be aware of when using it, so we will list the noteworthy points below.

Offered class

There are two class types for Reserved Instances, and you choose the one that is more appropriate for your situation.

standard

• Very cheap (up to 72% off compared to on-demand)
• Unable to change instance type midway
• Can be sold on the marketplace

convertible

• Higher than standard (up to 54% OFF compared to on-demand)
• You can change to an instance type whose price is higher than the type you purchased.
• Can't sell on marketplace

If you do not expect to change the instance type to be used, considering the service load and usage scenario, it is better to choose Standard! (Even if I make a mistake, it will still sell, so I feel safe)

How to purchase and apply

When purchasing a Reserved Instance, you will need to decide on the following items, so please do so before purchasing.

• Platform (Linux/Unix, Windows, Red Hat Enterprise Linux, etc.)
• Region or Availability Zone
• Tenancy (How to rent a server. Default is shared with others, dedicated is exclusive)
• Instance type (t2.micro, m4.large, etc.)
• Contract period (1 year or 3 years)
• Payment method (Choose from full prepayment, partial prepayment, or no prepayment.If you do not pay all in advance, pay the remaining amount every month)

Also, there is a quirk in how instances are applied, so you need to be careful here as well.
Reserved Instances are not tied to a specific instance and purchased are automatically applied if an instance that meets the conditions exists

For example, if you purchase a Reserved Instance with m4.large, Windows OS, default tenancy, and availability zone ap-northeast-3, it will be automatically applied if there is an EC2 instance that matches all the conditions.

*However, please be aware that once you purchase, you will be charged even if there are no instances that match the conditions or the instances are not started. Please note that it will not be applied if the region is different.

summary

In this article, we have limited the explanation to the very basics, but have you managed to get an overview of Reserved Instances?

There's not much to think about, and it's not difficult to purchase.

This is a very economical system for running and operating the same instance over a long period of time, so don't hesitate to use it wisely to reduce costs!