Hacker News new | past | comments | ask | show | jobs | submit login

I appreciate the effort that the authors have put in to synthesise all these points into this article, but I think I disagree with almost every one of the technical points.

1. Multiple Rates of Change: Why must changing one module in a monolith take longer than changing the same module in its own service? Perhaps a better use of time would be to improve CI+CD on the monolith.

2. Independent Life Cycles: Ditto. If the tests partition neatly across modules, why not just run the tests for those modules? If they don't, not running all your tests seems more likely to let bugs through, wasting the investment in writing said tests.

3. Independent Scalability: How bad is it to have a few more copies of the code for account administration module loaded even if it's not serving a lot of requests? The hot endpoints determine how many servers you need; the cold ones don't matter much. And load is stochastic: what is hot and what is cold will change over time and is not trivial to predict. If you separate the services, you have to over-provision every service to account for its variability individually, with no opportunity to take advantage of inversely correlated loads on different modules in the monolith.

4. Isolated Failure: Why not wrap the flaky external service in a library within the monolith? And if another persistence store is needed to cache, it is no harder to hook that up to a monolith.

5. Simplify Interactions: Ditto. The Fa├žade pattern works just as well in a library.

6. Freedom to choose the right tech: This is true, but as they say having all these extra technologies comes with a lot of extra dev training, dev hiring and ops costs. Maybe it would have been better to use a 'second best' technology that the team already has rather than the best technology that it doesn't, once those costs are accounted for.

The cultural points are largely valid for large organisations, but I feel like it positions microservices as an antidote to waterfall methods and long release cycles, which I think could be more effectively addressed with agile practices and CI+CD. Splitting out a service might certainly be a good way for a large organisation to experiment with those practices, however.




> 6. Freedom to choose the right tech: This is true, but as they say having all these extra technologies comes with a lot of extra dev training, dev hiring and ops costs. Maybe it would have been better to use a 'second best' technology that the team already has rather than the best technology that it doesn't, once those costs are accounted for.

A variation of this pushed me to implement a couple parts of an application as micro-services even though I wanted to stick with a monolith. I wanted to use existing open-source packages written in languages other than the primary one that I had chosen for my monolith. It's really a shame that a cross-language, in-process ABI like COM didn't catch on outside of Windows.


A cross language, in process ABI does exist for all platforms. It's called the C ABI. Almost every programming language can export and import C ABI functions and data.


Sure, but that's lower level than COM or WinRT. And in practice, does anyone embed, say, a Node.js module inside a JVM application via a C library?


I read the whole thing as "here are some factors that may nudge you toward micro services, within the broader context that splitting your app into micro services has a big pile of complexity and other costs".

So it's not that any of those factors necessarily mean micro services are the right answer, but that some combination of them might make micro the right answer for some slice of a system in some context.




Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact

Search: