Live data from Hacker News

Decoding AWS Reserved Instances

blog.symops.com

1–10 of 25 posts

Re: Decoding AWS Reserved Instances

#2
> Reserved Instances are a major piece of AWS Billing, accounting for $100B in revenue along side Saving Plans (SPs).

I think I know what you mean, but this reads like Reserved Instances earn AWS $100 billion/year which is almost impossible. I don't even think AWS earns that much annually.

Re: Decoding AWS Reserved Instances

#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't keep a running EC2 instance "filling" the reserved instance slot. 3. You're helping them with capacity planning and capacity management; there's no guesswork involved with your workload.

Re: Decoding AWS Reserved Instances

#4
This is written from an interesting angle and I'm not sure who it is meant to serve. It "and then's" Savings Plans but for the majority Saving Plans replace RI and are infinitely more flexible and easy to use.

TLDR if you are choosing RI's over Saving Plans the basic info conveyed in this article is probably already know if you don't you should probably just be choosing saving plans.

Re: Decoding AWS Reserved Instances

#5
Cool to see Vantage mentioned here! I work for them, mainly on the ec2instances.info site.

https://docs.vantage.sh/autopilot/ has many details on how our RI management program works. We recently added Autopilot Controls which lets you specify categories of instances (like c5) or regions that you want managed.

One note on buybacks: they are usually capped. I believe most providers cap their "guarantee" around $20K.

Re: Decoding AWS Reserved Instances

#6
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 what your Finance teams work with.

The original Reserved Instance product combined both of these. AWS now has the same decoupling with Savings Plans and Reservations as related, separate products.

Re: Decoding AWS Reserved Instances

#7
post #5

Cool to see Vantage mentioned here! I work for them, mainly on the ec2instances.info site. https://docs.vantage.sh/autopilot/ has many details on how our RI management program works. We recently added Autopilot Controls which lets you specify categories of instances (like c5) or regions that you want managed. One note on buybacks: they are usually capped. I believe most providers cap their "guarantee" around $20K.

I didn't know this page existed, but nice work. I like how you display this data and make is so easy to do comparisons. This is a great resource.

Re: Decoding AWS Reserved Instances

#8
Reserved instances are effectively a financial construct.

A lot of human hours go into managing them, buying them, selling them, making sure they are efficiently used, etc.

I do wonder if the human effort invested in such things is actually a net gain over a fixed price. Clearly there is gain for the companies using RI's, but is there gain for the economy as a whole?

Re: Decoding AWS Reserved Instances

#9

Reserved instances are effectively a financial construct. A lot of human hours go into managing them, buying them, selling them, making sure they are efficiently used, etc. I do wonder if the human effort invested in such things is actually a net gain over a fixed price. Clearly there is gain for the companies using RI's, but is there gain for the economy as a whole?

> Reserved instances are effectively a financial construct.

Almost true. It's also a powerful lock-in mechanism.

Re: Decoding AWS Reserved Instances

#10
This year some of my RIs became useless to me with a chunk of the 3-year term remaining, due to the EC2-Classic shutdown. (The instance types were a couple of generations old, and no longer available in the same availability zones in the VPC network.) Since understandably no one on the marketplace wanted to buy them, I asked AWS to credit me for the unused time on the RIs, with a promise that I'd spend the credit on new RIs on the latest generation hardware. They kept saying no -- RIs are a commitment, even if they become worthless due to their own mandates, apparently. I spent 40 days on a support ticket in which they'd go silent for a week at a time and then come back with an offer for a credit conditioned on me committing to buy way more RIs than I need. Finally they just bought my unused RIs from me on the marketplace at their full value. An acceptable outcome, but I should never have had to fight AWS for this credit.
Post reply on HN