Atlassian started rearchitecturing around services in 2013. They were 1500ppl at the time. Confluence and JIRA were not only monoliths, but non-multitenant, so they had to have one instance per customer (700Mb RAM JIRA, 700Mb Confluence, a dozen gigs on SSD). The worst was restarting upon upgrades: Easily 3-5 minutes per instance, which, at scale, was a huge burden.
After rearchitecting around services, pieces could be restarted and upgraded independently. As a customer, we didn't notice differences in the UI (e.g. the file storage on AWS).
Epilogue: They had a shared login system, multi tenant and all... which they recently replaced by a third party. Proof that services are replaceable, but also an acknowledgment that simple critical services can be hard at scale.
I personally believe that Atlassian switched to services at the right time, when it's hard to coordinate teams of thousands working on a dozen products, and when the monolithic approach was way past refactoring date ;)
Rather a late reply but Service Oriented Architecture is in fact an architectural approach. "Micro" services deem even the burdern of devising a coherent "service" as too great a burden to tackle.
> Confluence and JIRA were not only monoliths, but non-multitenant, so they had to have one instance per customer (700Mb RAM JIRA, 700Mb Confluence, a dozen gigs on SSD).
I don't understand how you engineer even a monolith like that in the first place.
After rearchitecting around services, pieces could be restarted and upgraded independently. As a customer, we didn't notice differences in the UI (e.g. the file storage on AWS).
Epilogue: They had a shared login system, multi tenant and all... which they recently replaced by a third party. Proof that services are replaceable, but also an acknowledgment that simple critical services can be hard at scale.
I personally believe that Atlassian switched to services at the right time, when it's hard to coordinate teams of thousands working on a dozen products, and when the monolithic approach was way past refactoring date ;)