Chapter 11 - Lifecycle Management

Abstract

This chapter discusses the two lifecycle management solutions offered by the WS-ResourceLifetime specification. Because lifecycle management mainly makes sense when there are several resources, the examples focus on explaining what modifications are necessary to the example seen in the factory/instance example. The version of that example with the lifecycle modifications can be found in directory EXAMPLES_DIR/org/globus/examples/services/core/rl/. Immediate destruction is the simplest type of lifecycle management. It allows to request that a resource be destroyed immediately by invoking a destroy operation in the instance service. Scheduled destruction is a more elaborate form of resource lifecycle management, as it allows specifying exactly when the resource is to be destroyed. The main application of scheduled destruction is to perform lease-based lifecycle management, where initially the destruction time of a resource is set some time in the future. This is called the lease. The application must periodically renew the lease (setting the destruction time another 5 minutes in the future), or the resource will eventually be destroyed. This will allow the application to purge resources from services that for some reason (network failure, programmer errors) have become unavailable (and therefore can't receive the lease renewal). Java WS Core includes an interface called RemoveCallback that, when implemented by a resource class, will allow to perform an action when the resource is going to be destroyed. GT4 includes a set of command-line clients one can use to destroy a resource or modify its termination time without having to write a client specifically for a certain service.