Expanding ourselves: the hosting service

Another thing our simple service doesn't do--because it's just not needed--is expand and contract as needed.

Controlling the number of access points is a nonsense idea, because access points are created whenever a client binds a warrant to access our service, and that's out of our control. But controlling the number of core netlets which run our service does make sense.

Looking back at our example Hello world service 3 we talked about a number of message servers which the access point netlets queried to get the message. Clearly if our hello world service was in high demand then we'd want more message servers to cope with demand, perhaps located in strategic locations around the world to get closer to the clients.

This is what a hosting service is for. Access to a hosting service allows us to send netlet descriptors onto its nodes for those nodes to run them. Therefore a fully-fledged Jtrix service will make use of several hosting services to spread itself out as needed. Again, Beatrix contains tools to make this relatively easy. Beatrix keeps several message servers running for Jtrix.org's hello world service, and all the service implementation worries about is how many it needs. Whenever a message server gets killed Beatrix notices and asks a hosting service to start another in its place.