Convertible Reserved Instance

 

Let’s say you’ve already purchased a Convertible RI and have since rightsized your instances. You can’t technically downsize a Convertible RI — the instance type that you convert to has to be of equal or greater value.

Trick is depicted in the given diagram.

First, convert your Convertible RI to t2.nano Linux RIs, which is the smallest and cheapest type of RI. It may mean that you’re converting your RI into dozens or even hundreds of t2.nano RIs.

Then from there, you can convert the t2.nano RIs to whatever RI type you wish.

Essentially, converting your larger RI to lots of small RIs is like converting a $100 bill into $1 bills, giving you the flexibility to trade up to a $10 bill, two $20 bills, and a $50 bill. You’re still spending the same amount (which gets around the Convertible RI limit). But you get to trade down to a smaller instance type and have leftover “change” to apply to another instance.