Microservices and SOA
When we've talked about microservices a common question is whether this is just Service Oriented Architecture (SOA) that we saw a decade ago. There is merit to this point, because the microservice style is very similar to what some advocates of SOA have been in favor of. The problem, however, is that SOA means too many different things, and that most of the time that we come across something called "SOA" it's significantly different to the style we're describing here, usually due to a focus on ESBs used to integrate monolithic applications.
In particular we have seen so many botched implementations of service orientation - from the tendency to hide complexity away in ESB's , to failed multi-year initiatives that cost millions and deliver no value, to centralised governance models that actively inhibit change, that it is sometimes difficult to see past these problems.
Certainly, many of the techniques in use in the microservice community have grown from the experiences of developers integrating services in large organisations. The Tolerant Reader pattern is an example of this. Efforts to use the web have contributed, using simple protocols is another approach derived from these experiences - a reaction away from central standards that have reached a complexity that is, frankly, breathtaking. (Any time you need an ontology to manage your ontologies you know you are in deep trouble.)
This common manifestation of SOA has led some microservice advocates to reject the SOA label entirely, although others consider microservices to be one form of SOA , perhaps service orientation done right. Either way, the fact that SOA means such different things means it's valuable to have a term that more crisply defines this architectural style.
7: We can't resist mentioning Jim Webber's statement that ESB stands for "Egregious Spaghetti Box".
8: Netflix makes the link explicit - until recently referring to their architectural style as fine-grained SOA.
PS--I focused on "microservices" after seeing a Linkedin post from AWS advertising a Webex on their support for development using microservices. Perhaps this Webex would address the obvious questions about managing latency/failure and managing security in a system made of lots of microservices.