Get off of my cloud

David Heinemeier Hansson’s blog post on his company’s move from the cloud back to their own servers is an interesting read:

I also think that there are probably some companies that have such high variance in their loads that renting makes sense. If you only need a plough thrice a year, it doesn’t make much sense keeping it in the barn unused for the remaining 363 days.

Perhaps this will increase the volume and awareness of more nuanced conversations about choosing the right application and organisational architecture, beyond a binary choice of cloud vs on-premises for everything.

One of the best articulations I’ve seen of how a cloud environment can work for an application is Troy Hunt’s explanation from 2018 of how he optimised haveibeenpwned.com using Cloudflare Workers and Azure Functions:

It’s costing me 2.6c per day to support 141M monthly queries of 517M records.

Just taking an application that is running on your own hardware and dumping it into the cloud is highly unlikely to yield any cost benefit unless it is re-architected and optimised to take advantage of the features of the cloud platform.

Hunt wrote a follow-up post last year, outlining how he suddenly received an eye-watering Azure bill after breaching a file size limit for a Cloudflare cache on his service. So even when you’re optimised, you need to be highly aware of the limits that apply to your setup, as well as having early warning alarms in place to catch anything that has gone wrong.

Cost is a major factor in determining a cloud versus on-premises architecture but there are other considerations too. Finding the right people with the right skillsets to run your own infrastructure is not trivial.

Hopefully the post won’t signal the start of a cyclical movement to and from the cloud, like the others that we already have in ‘enterprise’ technology — outsourcing/insourcing, offshoring/onshoring, centralisation/decentralisation etc.

Given Hansson’s company runs a product called HEY, since reading his post I haven’t been able to get this earworm out of my head. I suspect that this will be on my ‘internal hi-fi’ quite a lot over the next few years.