Chapter 14. RI and CUD Strategies
Now that you understand the fundamentals of reservations as described in the last chapter, it’s time to ask some tough but important questions:
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How much should you reserve?
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What should you reserve?
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When should you reserve?
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Who should be involved in the process?
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How do you know your RIs and CUDs are being fully utilized?
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How do you know when to repurchase them?
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Who should pay for them?
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How do you allocate the costs and savings over the reservation term?
Unfortunately, there are no definitive answers—only the answers that are right for a company at a particular time. Those answers may change considerably as you move through the FinOps maturity curve, as the cloud providers update their ever-changing commitment models, and as your company’s cash reserves change.
Common Mistakes
There are a number of errors that we see companies make when purchasing RIs and CUDs. In no particular order, these are:
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Delaying purchasing RIs too long
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Making purchases that are too conservative
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Buying based on the number of unique instances instead of a waterline
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Not managing RIs and CUDs after purchasing them
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Buying too many or too few RIs or CUDs
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Buying the wrong RIs or CUDs
Nearly everyone gets some part of their early strategy wrong. That’s OK. This is the Crawl stage. You can think of it like learning to ride a bike or writing your first bits of code—it’s a learning process that may take a few tries to get it right.
Failure sucks but ...