[jboss-as7-dev] Clustered invocation design

There are at least two basic paths we can follow for clustered invocation based on the current architecture. The right choice is going to depend primarily upon the expected use cases, which I am not in a position to properly judge. Option 1: Clustered Invocation Transport ---------------------------------------- In this option, we introduce a new "LAN" transport type for invocation on the cluster. The transport would use direct TCP connections or UDP messages (or both, depending on request size) to convey the invocation. The characteristics of this option are as follows: - Security: reliance on physical network security only (no TLS or authentication) - Latency is very low, even to new nodes - Topology changes can be conveyed as separate asynchronous messages - Invocations from external networks would happen through a proxy node, with Remoting being bridged to the LAN, to perform security functions Option 2: Load-balanced Remoting Connections -------------------------------------------- In this option, we rely on the client to establish one or more Remoting connection(s) to one or more of the nodes of the cluster. Logic in the client will be used to determine what connection(s) to use for what clusters. We have the option of automatically connecting as topology changes or requiring the user to set up the connections in advance. Note that automatic connection cannot work in the case of user-interactive authentication. Characteristics: - Security: full authentication and TLS supported - Latency is low once the connection is established, however there is some overhead involved in authentication and security negotiation - Topology changes should be asynchronous notifications - Each connection has to be separately authenticated - Automatically establishing connections is not presently supported, so we'd need a bit of infrastructure for that. Deal with user-interactive authentication. Deal with connection lifecycle management. Deal with configuration. This will be a point of fragility Summary ------- For both options, we have to determine an appropriate load-balancing strategy. The choice of direction will affect how our clustering and transaction interceptors function. We also have to suss out the logic around dealing with conflicting or wrongly-ordered topology updates; hopefully our existing policies will continue to apply. -- - DML