How Do I Stop Wasting Money on Reserved Instances?

“How do I stop wasting money on Reserved Instances?”

It’s a question we’ve heard before from despairing AWS users. They were told Reserved Instances (RIs) would save them money, so they purchased them. Now, halfway into a three-year contract, they realize they’re not utilizing the RIs they’re paying for. Or worse… they may not even know what RIs they have.

Amazon offers Reserved Instances to ostensibly help get your cloud costs in control. The message is that RIs help you save money on your EC2 instances by offering discounted hourly rates in exchange for a 1- or 3-year commitment. Before we get into how you can cut your cloud spending with an AWS RI, here’s a bit of background and what you need to know about AWS EC2 Reserved Instance pricing.

How do EC2 Reserved Instance Purchasing Options Work?

There are a few risks that come with the longer commitment times. For starters, if AWS drops pricing, then the promised savings are reduced or may disappear. And when AWS introduces a new generation of an instance type family it may attract your users away from your contracts — these are based on the older generation. If you don’t know your future needs, it may be appealing to use the 1-year instead of a 3-year contract, which has savings vs. On Demand at about 31–40%.

There are three different types of EC2 Reserved Instances that customers can purchase — Standard Reserved Instances, Convertible Reserved Instances, or Scheduled Reserved Instances. With Standard Reserved Instances, customers would see the most significant savings. However, Convertible Reserved Instances are attractive to customers because it gives them added flexibility like the ability to use different instance families, operating systems, or tenancies over the term. Scheduled RIs allow you buy an RI that is only used at certain times each day in a recurring schedule.

When an RI expires, you are charged again at the normal rate. See the recently released option to queue RI purchases in advance. This may help provide the greatest savings by eliminating gaps in your coverage from reservations.

Additional Ways To Save

You may also buy RIs on the Reserved Instance Marketplace from third-party sellers. The great thing about this is that these third parties tend to list their RIs at lower prices for a shorter period of time. And if you find you have too many RIs, you can sell them on the Marketplace as well.

Payment plans

Some may think that the need to pay upfront and be locked in undermines both “pay as you go” and the notion of being “elastic”- almost like a step backward to the old economic model.

An example of the savings offered by each EC2 RI option, along with the percent of savings each has over the On-Demand price is shown below. From these graphs, you can see that with a 3-year contract, your savings would be much greater. Other things to note is that you will have greater savings with Standard Instances, as well as if you choose the “All Upfront” payment plan. While you would receive discounted hourly rates for choosing Partial Upfront or No Upfront as a payment plan, if you can, All Upfront would be your best option with the most savings.

How should I use my Reserved Instances?

Reserved Instances are very much a “use it or lose it” proposition. In other words, there are no rollover minutes — if you don’t use your reserved instances one month you don’t get extra time the next month. Here’s why they are like this:

  • The EC2 options available are specific to Region, Availability Zone, Instance Type (e.g. m5.large) with some exceptions, Platform Type (e.g. Linux or Windows), and Tenancy. AWS, behind the scenes, attempts to randomly match instances you launch to the Reserved Instance contracts you have in place, based on the specific criteria. When there is a match, the cost benefit is applied. It is not uncommon for people to believe they are launching instances that match all the criteria, when in fact they are not, so the contracts are under-utilized. And you won’t know what matches were made until you get your bill at the end of the month.
  • AWS decrements the contract amount for every hour when not used, meaning your return on investment diminishes.
  • For every hour in your RI term, you pay the fee for hourly usage regardless of whether there has been any usage during that hour.

Given all of the tradeoffs mentioned above, Reserved Instances make the most sense in a production environment, where instances need to always be “on.”

How ParkMyCloud Can Help Manage Your Reserved Instances

With ParkMyCloud, you can create parking schedules that automatically turn EC2 instances on and off according to your specifications. ParkMyCloud provides customized parking recommendations based on criteria provided by the user, which makes identifying “parkable” instances easier — and you can automatically accept these recommendations if you like. Turning this into an automated process cuts down on time and costs, thus further optimizing your cloud environments. Another perk of ParkMyCloud is that the platform tracks costs, projected 30-day savings, and actual savings for the current month — giving you better visibility.

ParkMyCloud easily achieves EC2 savings of 50–73% with no annual commitment, upfront payment, or risk of instance termination or price cuts. In fact, we had a customer cancel a $10,000 order for AWS Reserved Instances in favor of EC2 instances that they could turn on and off after they found out just how easy and powerful this cost savings tool can be. Here are some of the advantages that come with using ParkMyCloud:

  • Better savings
  • No commitment or upfront payment
  • Price cut protection

Try out ParkMyCloud for yourself and get started parking your non-production systems and RightSizing your resources to ensure that your environments are running in the most efficient way possible.

Originally published at www.parkmycloud.com on October 31, 2019.

CEO of ParkMyCloud