Cluster Administrative Domain APIs

The information provided here includes:


Cluster administrative domain APIs--introduction

The cluster administrative domain APIs enable the management of resources which need to be maintained consistently across the nodes in a clustered environment. You can create the cluster administrative domain by specifying the cluster nodes which make up the operational environment. Within this domain, you can specify resources which need to be monitored by adding them to the domain as Monitored Resources. When a change is made to a monitored resource on any node in the domain, that change is synchronized across the other active nodes in the domain, in order to maintain the consistency of the resource.

A cluster administrative domain is created with the Create Cluster Administrative Domain (QcstCreateClusterAdminDomain) API.

Once a cluster administrative domain is created, any of the other cluster administrative domain APIs may be called from any node in the cluster administrative domain. Additionally, the Change Cluster Administrative Domain, Add Monitored Resource Entry, and Remove Monitored Resource Entry APIs require that all nodes in the cluster administrative domain are active and not partitioned.

It may be determined that the synchronization option of a cluster administrative domain needs to be changed. A cluster administrative domain is created with a default synchronization option of Last Change, which means that the last change made to a monitored resource is applied to the active domain when a node rejoins the cluster, regardless of whether the change was made on the joining node or in the active domain. The synchronization option can be changed with the Change Cluster Administrative Domain (QcstChangeClusterAdminDomain) API.

Since the purpose of a cluster administrative domain is to maintain consistent resources, adding a monitored resource to the domain is an important step. When a cluster administrative domain monitors a resource, it specifically monitors for changes to a set of attributes for that resource. You may choose to monitor either all, or a subset of, the attributes for a resource. The Retrieve Attribute Names (QmrRtvAttributeNames) API can be used to retrieve the eligible attributes for a resource. Adding a monitored resource to a cluster administrative domain, which includes specifying the set of attributes to monitor, is accomplished with the Add Monitored Resource Entry (QfpadAddMonitoredResourceEntry) API.

Once resources are monitored by a cluster administrative domain, status information about the monitored resources can be retrieved with the Retrieve Monitored Resource Information (QfpadRtvMonitoredResourceInfo) API. The information retrieved includes whether the resource is currently synchronized and the value to which each attribute is being synchronized. The format of these values is determined by the data type of the attribute. See Monitored Resource Entry Data Types for more information about the structure of the values retrieved based on the data type.

When a resource no longer needs to be monitored, the resource can be removed from the cluster administrative domain using the Remove Monitored Resource Entry (QfpadRmvMonitoredResourceEntry) API. Removing the monitored resource entry only stops the cluster administrative domain from monitoring the resource. It does not actually delete the resource.

Qibm_cst_admdmn exit point

For every type of resource that can be monitored by a cluster administrative domain, there is information in the Registration Facility which provides a cluster administrative domain with information required for monitoring a resource of that type. This information is represented by an exit program associated with the IBM®-supplied QIBM_QCST_ADMDMN exit point (ADMN0200 format) for each resource type. There is one registered exit program entry for each monitored resource type. These exit programs cannot be removed from the exit point, nor can additional exit programs be added to the exit point.

Each exit program represents the service program used by a cluster administrative domain to enable the monitoring of a resource type. The exit program data specified by the ADMN0200 format identifies specific characteristics of the supported resource type. The exit program data can be retrieved by using the Retrieve Exit Information (QusRetrieveExitInformation) API.

Exit program data (admn0200 format)

The following information is returned as exit program data for the ADMN0200 format. This format provides information about a monitored resource type. For a detailed description of each field, see Field Descriptions.



Field Descriptions

Cluster modification level. The first cluster modification level for which the resource type is supported by a cluster administrative domain.

Cluster version. The first cluster version for which the resource type is supported by a cluster administrative domain.

Library. The name of the library for resource types that always exist in a specific library. If resources of the specified resource type do not exist in a library or do not have to exist in a specific library, this field will be set to blanks.

Name option. Indicates whether the name of a resource of the specified resource type is limited to a 10 character object name. The possible values are:

Object message ID. The identifier for the message used to display the name of the object type for the specified resource type.

Object type. The object type represented by the specified resource type. Several resource types can map to one object type. For example, the resource types *OPTDEV (optical device description) and *TAPDEV (tape device description) both map to the object type *DEVD (device description). If the resource type is not a system object, this field is set to blanks.

Reserved. Set to blanks.

Resource type. The resource type supported by the exit program. Supported resource types are:

Resource type option. Specifies the category that resources of the specified resource type fit into. The possible values are:



Monitored resource entry data types

The format for the value of each attribute retrieved by the Retrieve Monitored Resource Information (QfpadRtvMonitoredResourceInfo) API when the DENR0200 and DENR0300 format is used, is determined by the data type for each attribute. The following table maps the data type to the structure used to represent the value.



Cluster administrative domain API list

The cluster administrative domain APIs include:



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