But what mistakes did he make?
Did he screw up the bill? Did he fail to keep services available? I only read facts about the ins and outs of AWS' billing and credits system.
If you run out of CPU or IOPS burst balance then your system will suddenly slow to a crawl and it can easily cause downtime or in the case of background jobs it will cause long queues or never ending jobs. Learned that the hard way, a couple times.
One time I optimized DB access which fixed the IOPS usage, and then that caused more CPU usage on the app servers which caused them to run out of CPU burst... Fun times. Switched from one burst issue to another.
I disagree this is about scaling systems. This is actually more about using the wrong instance type. If this was on a typical VPS it wouldn't have ever happened. The baseline CPU level on these burst instances is so low that for any long running task using even like 40% CPU it gets throttled so hard it brings everything down. I would have been totally fine if this was a $5 DigitalOcean VPS
