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Oracle Solaris Cluster Data Services Developer's Guide     Oracle Solaris Cluster 4.0
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Document Information


1.  Overview of Resource Management

2.  Developing a Data Service

Analyzing the Application for Suitability

Determining the Interface to Use

Setting Up the Development Environment for Writing a Data Service

How to Set Up the Development Environment

Transferring a Data Service to a Cluster

Setting Standard Properties

Cluster Properties

Resource Type Properties

Resource Properties

Resource Group Properties

Resource Property Attributes

Node List Properties

Setting Resource and Resource Type Properties

Declaring Resource Type Properties

Declaring Resource Properties

Declaring Extension Properties

Implementing Callback Methods

Accessing Resource and Resource Group Property Information

Idempotence of Methods

How Methods Are Invoked in Zones

Generic Data Service

Controlling an Application

Starting and Stopping a Resource

Using Start and Stop Methods

Deciding Which Start and Stop Methods to Use

Using the Optional Init, Fini, and Boot Methods

Using the Init Method

Using the Fini Method

Guidelines for Implementing a Fini Method

Using the Boot Method

Monitoring a Resource

Implementing Monitors and Methods That Execute Exclusively in the Global Zone

Adding Message Logging to a Resource

Providing Process Management

Providing Administrative Support for a Resource

Implementing a Failover Resource

Implementing a Scalable Resource

Validation Checks for Scalable Services

Writing and Testing Data Services

Using TCP Keep-Alives to Protect the Server

Testing HA Data Services

Coordinating Dependencies Between Resources

Legal RGM Names

RGM Legal Names

Rules for Names Except Resource Type Names

Format of Resource Type Names

RGM Values

3.  Resource Management API Reference

4.  Modifying a Resource Type

5.  Sample Data Service

6.  Data Service Development Library

7.  Designing Resource Types

8.  Sample DSDL Resource Type Implementation

9.  Oracle Solaris Cluster Agent Builder

10.  Generic Data Service

11.  DSDL API Functions

12.  Cluster Reconfiguration Notification Protocol

A.  Sample Data Service Code Listings

B.  DSDL Sample Resource Type Code Listings

C.  Requirements for Non-Cluster-Aware Applications

D.  Document Type Definitions for the CRNP

E. Application


Implementing Callback Methods

This section provides general information that pertains to implementing the callback methods.

Accessing Resource and Resource Group Property Information

Generally, callback methods require access to the properties of the resource. The RMAPI provides both shell commands and C functions that you can use in callback methods to access the system-defined and extension properties of resources. See the scha_resource_get(1HA) and scha_resource_get(3HA) man pages.

The DSDL provides a set of C functions (one function for each property) to access system-defined properties, and a function to access extension properties. See the scds_property_functions(3HA) and scds_get_ext_property(3HA) man pages.

You cannot use the property mechanism to store dynamic state information for a data service because no API functions are available for setting resource properties other than Status and Status_msg. Rather, you should store dynamic state information in global files.

Note - The cluster administrator can set particular resource properties by using the clresource command or through a graphical administrative command or interface. However, do not call clresource from any callback method because clresource fails during cluster reconfiguration, that is, when the RGM calls the method.

Idempotence of Methods

In general, the RGM does not call a method more than once in succession on the same resource with the same arguments. However, if a Start method fails, the RGM can call a Stop method on a resource even though the resource was never started. Likewise, a resource daemon could die of its own accord and the RGM might still run its Stop method on it. The same scenarios apply to the Monitor_start and Monitor_stop methods.

For these reasons, you must build idempotence into your Stop and Monitor_stop methods. In other words, repeated calls to Stop or Monitor_stop on the same resource with the same arguments must achieve the same results as a single call.

One implication of idempotence is that Stop and Monitor_stop must return 0 (success) even if the resource or monitor is already stopped and no work is to be done.

Note - The Init, Fini, Boot, and Update methods must also be idempotent. A Start method need not be idempotent.

How Methods Are Invoked in Zones

If declared in the RTR file, the Global_zone resource type property indicates whether the methods of a resource type execute in the global zone. If the Global_zone property equals TRUE, methods execute in the global zone even if the resource group that contains the resource is configured to run in a non-global zone.

If the resource for which Global_zone equals TRUE is configured in a non-global zone, methods that are invoked in the global zone are invoked with the -Z zonename option. The zonename operand specifies the Oracle Solaris zone name of the non-global zone in which the resource is actually configured. The value of this operand is passed to the method.

If the resource is configured in the global zone, the -Z zonename option is not invoked and the non-global zone name is not passed to the method.

The Global_zone resource type property is described in more detail in Resource Type Properties and in the rt_properties(5) man page.