The Hub serverΒΆ

The hub server is a master that can be connected like a pipeline. It therefore needs some more information to be added to a cluster. Instead of pulling from clients, it subscribes to a stream of messages coming from a master or a server. This is the reason why you have a sub connection instead of a pull service, and you have to take into account when configuring it.

There is yet another change respect to a master server, the previous parameter. If you don’t want to play dirty tricks to the message stream, i.e. routing a message to a particular subscribed server, it’s just the name of the previous server the hub is subscribed to.

Maybe the simplest stream of messages involving a hub is the following.

_images/server_hub.png

You can see an example how the output of a server can be pipelined to a hub in the example Connecting a hub to a server.