I would say they are both the fruit of the "ownership tree".
Both are solutions to big but specific problems.
(DevOps was a push against crazy corporate IT, where developers handed over the sacred tomes of operational manual and the blessed JAR/WAR files and IT took over from there. And operations was on-call, and ... had absolutely zero fucking idea what to do, the manuals were fake, and they had no expertise, and the whole handover was just burning money, etc. So dev teams got access, and things got a bit more programmatic anyway as scale kept growing. From the early days of Capistrano and Puppet to immutable images running on EC2 and nowadays to CI/CD with containers running wherever.
Microservies was kind of an organic step from that. Both to handle resource scaling and mostly to handle product/project coordination. Extremely limited scopes helps local reasoning to make okayish decisions most of the time.
See also Rust's ergonomics principles about "reasoning footprint" and the Bounded Context concept from DDD.
Of course the trick is that, it looks easy when someone gives a talk at a conference showcasing their company's a-ma-zing whiteboard-to-yet-another-webservice tempo, but it needs well-funded, good-faith constructive/supportive security and platform teams. And in practice it's famously hard to keep these complex interconnected systems/projects/orgs on track. And even when you have that many companies then try to force things [the good old hammer-nail anti-pattern] https://www.youtube.com/watch?v=PAew2jhr2zs )
"And operations was on-call, and ... had absolutely zero fucking idea what to do, the manuals were fake, and they had no expertise, and the whole handover was just burning money, etc."
This is what is we with DevOps now. The short lived dev teams had it over to the next dev team with basically no documentation. DevOps was just another stop on the shitty process parade that Agile contributed to - all about speed, forget docs, who has time for real tests, and for requirements we'll just use JIRA tickets the devs work on.
Surprise, surprise... Our bug and rework stories take about 25% of our capacity now.
Both are solutions to big but specific problems.
(DevOps was a push against crazy corporate IT, where developers handed over the sacred tomes of operational manual and the blessed JAR/WAR files and IT took over from there. And operations was on-call, and ... had absolutely zero fucking idea what to do, the manuals were fake, and they had no expertise, and the whole handover was just burning money, etc. So dev teams got access, and things got a bit more programmatic anyway as scale kept growing. From the early days of Capistrano and Puppet to immutable images running on EC2 and nowadays to CI/CD with containers running wherever.
Microservies was kind of an organic step from that. Both to handle resource scaling and mostly to handle product/project coordination. Extremely limited scopes helps local reasoning to make okayish decisions most of the time.
See also Rust's ergonomics principles about "reasoning footprint" and the Bounded Context concept from DDD.
Of course the trick is that, it looks easy when someone gives a talk at a conference showcasing their company's a-ma-zing whiteboard-to-yet-another-webservice tempo, but it needs well-funded, good-faith constructive/supportive security and platform teams. And in practice it's famously hard to keep these complex interconnected systems/projects/orgs on track. And even when you have that many companies then try to force things [the good old hammer-nail anti-pattern] https://www.youtube.com/watch?v=PAew2jhr2zs )