Configures the Group Management Service (GMS), an in-process service that provides cluster monitoring, cluster membership, and group communication services. The GMS performs the following functions:
Notifies registered modules in an Enterprise Server instance when one or more member instances are added to or removed from a cluster, or are suspected or confirmed to have failed.
Provides the ability to send and receive messages between a group of processes.
The GMS is built atop a configurable stack of group membership discovery and health monitoring protocols. These protocols have properties that can be changed for a given network and deployment topology. Protocols in the GMS are as follows:
Failure detection protocol - enables its members to periodically monitor other group members to determine their availability in the group.
Discovery protocol - is used for discovery of the group and its members.
Verify failure protocol - verifies suspect instances by adding a verification layer to mark a failure suspicion as a confirmed failure.
Some topics in the documentation pertain to features that are available only in domains that are configured to support clusters. Examples of domains that support clusters are domains that are created with the cluster profile or the enterprise profile. For information about profiles, see Usage Profiles in Sun GlassFish Enterprise Server 2.1 Administration Guide.
The following table describes subelements for the group-management-service element.
Table 1–65 group-management-service Subelements
Element |
Required |
Description |
---|---|---|
zero or more |
Specifies a property or a variable. |
The following table describes attributes for the group-management-service element.
Table 1–66 group-management-service Attributes
Attribute |
Default |
Description |
---|---|---|
3 |
(optional) Specifies the maximum number of monitoring attempts before the GMS confirms that a failure is suspected in the group. |
|
2000 |
(optional) Specifies the time between monitoring attempts. |
|
2000 |
(optional) Specifies the time that the GMS waits for discovery of other members in the group. |
|
1500 |
(optional) Specifies the timeout after which a suspected failure is marked as verified. |