Sun Cluster 3.1 Concepts Guide

Resources, Resource Groups, and Resource Types

Data services utilize several types of resources: applications such as Apache Web Server or Sun ONE Web Server utilize network addresses (logical hostnames and shared addresses) upon which the applications depend. Application and network resources form a basic unit that is managed by the RGM.

Data services are resource types. For example, Sun Cluster HA for Oracle is the resource type and Sun Cluster HA for Apache is the resource type SUNW.apache.

A resource is an instantiation of a resource type that is defined cluster wide. There are several resource types defined.

Network resources are either SUNW.LogicalHostname or SUNW.SharedAddress resource types. These two resource types are pre-registered by the Sun Cluster software.

The SUNW.HAStorage and HAStoragePlus resource types are used to synchronize the startup of resources and disk device groups upon which the resources depend. It ensures that before a data service starts, the paths to cluster file system mount points, global devices, and device group names are available. For more information, see “Synchronizing the Startups Between Resource Groups and Disk Device Groups” in the Sun Cluster 3.1 Data Service Planning and Administration Guide. (The HAStoragePlus resource type became available in Sun Cluster 3.0 5/02 and added another feature, enabling local file systems to be highly available. For more information on this feature, see HAStoragePlus Resource Type.)

RGM-managed resources are placed into groups, called resource groups, so that they can be managed as a unit. A resource group is migrated as a unit if a failover or switchover is initiated on the resource group.

Note –

When you bring a resource group containing application resources online, the application is started. The data service start method waits until the application is up and running before exiting successfully. The determination of when the application is up and running is accomplished the same way the data service fault monitor determines that a data service is serving clients. Refer to the Sun Cluster 3.1 Data Service Planning and Administration Guide for more information on this process.

Resource Group Manager (RGM)

The RGM controls data services (applications) as resources, which are managed by resource type implementations. These implementations are either supplied by Sun or created by a developer with a generic data service template, the Data Service Development Library API (DSDL API), or the Resource Management API (RMAPI). The cluster administrator creates and manages resources in containers called resource groups. The RGM stops and starts resource groups on selected nodes in response to cluster membership changes.

The RGM acts on resources and resource groups. RGM actions cause resources and resource groups to move between online and offline states. A complete description of the states and settings that can be applied to resources and resource groups is in the section Resource and Resource Group States and Settings. Refer to Resources, Resource Groups, and Resource Types for information about how to launch a resource management project under RGM control.

Resource and Resource Group States and Settings

An administrator applies static settings to resources and resource groups. These settings can only be changed through administrative actions. The RGM moves resource groups between dynamic “states.” These settings and states are described in the following list.

Resource and Resource Group Properties

You can configure property values for resources and resource groups for your SunPlex data services. Standard properties are common to all data services. Extension properties are specific to each data service. Some standard and extension properties are configured with default settings so that you do not have to modify them. Others need to be set as part of the process of creating and configuring resources. The documentation for each data service specifies which resource properties can be set and how to set them.

The standard properties are used to configure resource and resource group properties that are usually independent of any particular data service. The set of standard properties is described in an appendix to the Sun Cluster 3.1 Data Service Planning and Administration Guide.

The RGM extension properties provide information such as the location of application binaries and configuration files. You modify extension properties as you configure your data services. The set of extension properties is described in the Sun Cluster 3.1 Data Service Planning and Administration Guide.