Chapter 1 Introduction

Web service high availability

Because the SOAP servlet runs as a Web application in EAServer, clients using EAServer Web services have the benefit of EAServer's high availability features. By creating a server cluster (a group of servers running on different machines), clients accessing EAServer Web services through a Web redirector automatically switch over to another member server in the cluster if the first server it attempted to connect to was unavailable. You can also configure the Web server redirector plug-in that you install on the Web server host, to forward requests for Web services to different servers in a cluster, based on availability. Failover to handle SOAP servlet failures will be supported in future releases. For more information on high availability and the Web server redirector plug-in, see the EAServer System Administration Guide.

You can further ensure high availability using the Web Services Toolkit GUI to specify multiple Web servers on which you have installed the Web Server redirector plug-in. By specifying addresses for the location of more than one redirector, the Web service client can have alternate EAServer clusters to access, if the first redirector is not available.

If you don't have a Web server with the redirector plug-in and a cluster set up, but you do have multiple EAServers with installed Web services, you can specify in the GUI multiple addresses. At runtime, if the first address selected is unavailable, the client tries each subsequent address until a connection is made or all addresses have been attempted. This feature helps ensure that EAServer Web services will be available whenever they are invoked.