Chapter 22. Stand-Alone Coordination
22.1. Introduction
The XTS service is deployed as a JBoss service archive (SAR). The version of the service archive provided with the Transaction Service implements version 1.1 of the WS-C, WS-AT and WS-BA services. You can rebuild the XTS service archive to include both the 1.0 and 1.1 implementations and deploy them side by side. See the service archive build script for further details.
The release service archive obtains coordination contexts from the Activation Coordinator service running on the deployed host. Therefore, WS-AT transactions or WS-BA activities created by a locally-deployed client application are supplied with a context which identifies the Registration Service running on the client's machine. Any Web Services invoked by the client are coordinated by the Transaction Protocol services running on the client's host. This is the case whether the Web Services are running locally or remotely. Such a configuration is called local coordination.
You can reconfigure this setting globally for all clients, causing context creation requests to be redirected to an Activation Coordinator Service running on a remote host. Normally, the rest of the coordination process is executed from the remote host. This configuration is called stand-alone coordination.
Reasons for Choosing a Stand-Alone Coordinator
- Efficiency: if a client application invokes Web Services on a remote Enterprise Application Platform server, coordinating the transaction from the remote server might be more efficient, since the protocol-specific messages between the coordinator and the participants do not need to travel over the network.
- Reliability: if the coordinator service runs on a dedicated host, there is no danger of failing applications or services affecting the coordinator and causing failures for unrelated transactions.
- A third reason might be to use a coordination service provided by a third party vendor.
