Microsoft’s Orleans, a good ideas

I came up in the days when Microsoft and Linux were mortal enemies. Back when “Borg Bill Gates” was the icon for stories about MS on Slashdot. Back when Slashdot was the cutting edge.

Thus, I’m always slightly surprised when I come across some really solid work done by Microsoft. The people at Microsoft are capable of really great work, but it often doesn’t escape The System in place between the hands on keyboards and the public face of the company.

Microsoft Research, in particular, produces surprisingly good research papers. The recent paper on Orleans is a great example.

Orleans is an opinionated “virutalized” actor framework MS developed that runs on their .NET and Azure frameworks:

  • The design is single-threaded, small timemeslices, no preemption; not unlike Go’s goroutines (when considered on only one host)
  • Orleans has its own runtime for activating, deactivating, locating, and dispatching to actors
  • Semantics end up looking like a combination of queue-workers, actors, and Promise-based systems

Implementing Orleans instead of a three-tier (web, app, DB) system allowed them to eliminate the need for a caching layer once they reached scale. Actors encapsulate state and caching thereof instead.

  • Virtualized actors become analogous to virtual memory, raising the level of abstraction programmers can work at
  • Virtualized actors don’t require management by operators or developers; failure and load-balancing behavior is managed by the runtime instead of prior specification
  • Currently implements at-least-once message semantics, which works for developers; considering added only-once message delivery

Orleans is currently in use in the Halo 4 presence and statistics services. I bet you’ll see clones and shallow carbon copies of these ideas in a language or conference near you. Read the paper, it’s quite accessible as distributed systems papers go. There are some nice ideas in there.

Ed. Let me know if you like reading notes on papers I’ve read. I’d like to do it more often if folks find it useful.