Uber is running private data centers, not using public cloud
It is also not using Kubernetes, instead has has developed its own cluster scheduler.
It is moved from node.js to GoLang for performance.
It has also moved from Posgres to MySQL, and running "schemaless" datastore.
It has a LOT of data, and running ML on that.
Uber Infrastructure with Prashant Varanasi and Akshay Shah - Software Engineering Daily
Peloton: Uber's Cluster Scheduler with Min Cai and Mayank Bansal - Software Engineering Daily
Why Uber Engineering Switched from Postgres to MySQL | Uber Engineering Blog
Designing Schemaless, Uber Engineering's Scalable Datastore Using MySQL | Uber Engineering Blog
"...key-value store which allows you to save any JSON data without strict schema validation, in a schemaless fashion (hence the name). It has append-only sharded MySQL with buffered writes to support failing MySQL masters and a publish-subscribe feature for data change notification"
Uber's Big Data Platform: 100+ Petabytes with Minute Latency | Uber Engineering Blog