Microservices in context

An interview with John Allspaw, on Etsy infrastructure and operations:

For example, a good friend of mine runs and has run an electronic trading exchange. You could imagine his goals and constraints when designing an electronic trading exchange are very different than, say, Facebook. Facebook might be very different architecturally because they have different constraints than Amazon. And Amazon might be different than even Etsy.

When you have a conversation that unnecessarily paints the discussion as, “Are you micro-services or are you a monolith?” then it wipes away all of the context-specificity. Which you actually have no real way of talking inspecifics.

Compared to the previous buzzword, SOA, what does microservices mean? As far I can tell, its two things:

  • A Rorschach test. What do you see in this buzzword? What does it say to you?
  • A signaling mechanism. I’m most likely to hear about microservices from those trying to distinguish themselves from those other people who write code that doesn’t share their values.

Context-specificity is the important part. I’ve been reading David Byrne’s How Music Works and he spends the first chapter entirely on how the performance venue (a savannah, a noisy club, an austere concert hall) puts its mark on the music that is performed there (percussion oriented, loud and compressed, or quiet and precise).

In architecture, context is also king. Building and deploying services is different at Heroku, Netflix, Facebook, and the place where you work. You can build services of varying size and complexity anywhere on any stack. What the team, culture, and organization prefers is the real determinant.

I find it useful to read about other people’s service architectures to learn what works elsewhere. Even better if they describe the context they built that service architecture in. But it is always foolish cargo-culting to attempt to replicate another team’s architecture without the team and organizational context in which it was born.