Sun Cluster 3.1 Data Services Developer's Guide

Programming Interfaces

For writing data service code, the resource management architecture provides a low-level, or base API, a higher-level library built on top of the base API, and a tool, SunPlex Agent Builder, that automatically generates a data service from some basic inputs you provide.

Resource Management API

The Resource Management API (RMAPI) provides a set of low-level routines that enable a data service to access information about the resources, resource types and resource groups in the system, request a local restart or failover, and set the resource status. You access these functions through the library. The RMAPI provides these callback methods both in the form of shell commands and in the form of C functions. See scha_calls(3HA) and Chapter 4, Resource Management API Reference for more information on the RMAPI routines. Also see Chapter 5, Sample Data Service for examples of how to use these routines in sample data service callback methods.

Data Service Development Library (DSDL)

Built on top of the RMAPI is the Data Service Development Library (DSDL), which provides a higher-level integrated framework while retaining the underlying method-callback model of the RGM. The DSDL brings together various facilities for data-service development, including:

For the majority of applications, the DSDL provides most or all of the functionality you need to build a data service. Note, however, that the DSDL does not replace the low-level API but encapsulates and extends it. In fact, many DSDL functions call the functions. Likewise you can directly call functions while using the DSDL to code the bulk of your data service. The library contains the DSDL functions.

See Chapter 6, Data Service Development Library (DSDL) and the scha_calls(3HA) man page for more information about the DSDL.

SunPlex Agent Builder

Agent Builder is a tool that automates the creation of a data service. You input basic information about the target application and the data service to be created.Agent Builder generates a data service, complete with source and executable code (C or Korn shell), customized RTR file, and a Solaris package.

For most applications, you can use Agent Builder to generate a complete data service with only minor manual changes on your part. Applications with more sophisticated requirements, such as adding validation checks for additional properties, might require work that Agent Builder cannot do. However, even in these cases you might be able to use Agent Builder to generate the bulk of the code and manually code the rest. At minimum, you can use Agent Builder to generate the Solaris package for you.