Microsoft Orleans

Start With Purpose

Do not begin with an Orleans API. First state:

1. the business identity that owns the behavior;
2. the invariant and what must survive activation or cluster failure;
3. the required consistency, query shape, acknowledgement, durability, replay, fan-out, and timing.

Then select the smallest Orleans primitive whose guarantees match those requirements. Reject Orleans when the problem is primarily shared-memory computation, a finite batch, relational querying, or global coordination with few independent entities.

Inspect package versions for version-sensitive work. Orleans 10.3.1 ships Microsoft.Orleans.DurableJobs* and Microsoft.Orleans.Journaling* as 10.3.1-alpha.1; treat them as experimental until that status changes.

Orleans 10.3 makes Newtonsoft storage enforce the type allow-list, changes RPC telemetry keys, and requires custom grain-context activators to apply configurators before construction. Prefer generated/allowed types over permissive JSON and update affected tests, dashboards, and activators together. 10.3.1 services analyzer contract identities and documents placement hints.

Mental Model