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Decoding AWS Reserved Instances

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Re: Decoding AWS Reserved Instances

#21

Post by rescbr »

jsmith45 wrote: post #20
jedberg wrote: post #11

This article talks about the financial pros and cons of reserved instances, but not the important operational benefit: You will always get an instance when you need it, and never get an error about not having enough instances of a certain type. This is critical if you are using autoscaling, especially during an outage. If you are shifting your workload from one region to another at the same time as everyone else, if…

That actually depends. Reserved instances have one form with zero operation benefits: Regional Reserved Instances. These are 100% purely billing constructs. They have zonal Reserved Instances which do reserve capacity. Finally they have pure capacity reservations. These cost full price. Esentially you are paying for an instance even if it is not running, but it does guarentee it will be there if you need it. but it a…

> However combining the capacity reservation with a savings plan allows you to basically recreate the net effect of a zonal Reserved Instance but with additional flexibility.

This is something that has never crossed my mind. TIL.

Re: Decoding AWS Reserved Instances

#22

Post by vosper »

scarytom wrote: post #19
vosper wrote: post #16

> Businesses can sell RIs they’ve purchased, setting their own price for the remainder of the contract. You can't sell convertible RIs, I thought? Would love to find out that's wrong. From what I've seen RIs are a trap, suitable to hardly anyone, especially not startups. If your infra is elastic or evolving at all, be really careful before going for RIs. And I would never go for more than a one year reserve. (maybe i…

You are correct, you cannot sell Convertible RIs on the RI Marketplace. I think it is going too far to say that RIs are a trap: the rules are pretty transparent. I agree with you that if your infra is elastic or evolving then you need to be very cautious about making large or long-term commitments.

I think the convertibles are a bit of a trap, though - even though the rules are transparent. You might overprovision to begin with (which you may not realise), then you can't even sell them.

Re: Decoding AWS Reserved Instances

#23

Post by StopHammoTime »

vosper wrote: post #16

> Businesses can sell RIs they’ve purchased, setting their own price for the remainder of the contract. You can't sell convertible RIs, I thought? Would love to find out that's wrong. From what I've seen RIs are a trap, suitable to hardly anyone, especially not startups. If your infra is elastic or evolving at all, be really careful before going for RIs. And I would never go for more than a one year reserve. (maybe i…

Almost everyone has some kind of base workload, whether it’s RDS or EC2 operating some specific piece of infra.

Some people may not be able to RI their entire workloads, but EVERYONE can reduce their AWS spend partially using RIs. It may only be a little bit but better in your pocket than Amazons.

Re: Decoding AWS Reserved Instances

#24

Post by efitz »

boulos wrote: post #6
efitz wrote: post #3

It probably would have been better if AWS had called them "reservations" rather than "reserved instances". NB they would never call it a lease or rental because those terms have legal repercussions in some jurisdictions. A reserved instance is simply pre-paying for a specific amount of EC2. AWS is able to discount this because: 1. You're pre-paying 2. You might not use all the resources you're entitled to, if you don…

Disclosure: I used to work on GCE. We got to go second, but I prefer the naming and separation of concerns we came up with (obviously): Reservations are capacity you're holding, while Commitments are things that get you discounts. Reservations are things your operations team uses to guarantee capacity for scaling up, doing rolling restarts, and whatever else. Commitments (and Committed Use Discounts) are primarily wh…

I’m not familiar with GCP but those names/concepts are easy to understand and I like the separation of concepts.
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