Partition Service Architecture Documentation
The API for the Partition Service is very straight-forward. But when looking at the effect of adding a new partition to the system is on topics like ingestion, search and security; then it is actually a very complex topic to explain an manage for users/customers.
For example: adding partition means carefully updating all users and groups in the entitlements service: clearly mapping out which groups end-up in which partition when viewing it from a user base or mapping what data is available to what groups when viewing it from a partition base (i.e. it is not the first time it is not clear that a group in an ACL for data in a partition is not mapped to any of the groups in the entitlements service or at least there are no users with access to that particular partition).
A clear document describing cause, effect and expectations from an operations perspective is very much desired.