I'm involved in a project that uses Orleans. Conceptually and technically it's very interesting. Nodes automatically cluster together to form a big distributed system, and the concept of "virtual actors" make it possible to represent individual entities in the data model directly as actors, without worrying whether everything fits in memory at the same time.

However, Orleans doesn't seem to play very well with Kubernetes. Kubernetes pods can be uncleanly terminated at any time for any reason. Orleans really doesn't like unclean shutdowns: it will leave behind dead entries in the membership tables, which then cause problems in the future because new nodes would contact dead members and run into errors.

The clustering protocol also seems to assume that all members have stable identities and IP addresses, but that's obviously not the case in Kubernetes, where each new pod has a new identity and new IP address. This can cause members to fail uncleanly, which in turn pushes the clustering protocol into an infinite loop.

Orleans was introduced by one person who has a background in distributed computing. Unfortunately, he's the only one in the organization with such a background. After he left, nobody could debug clustering problems.