If a core group includes a cluster of application servers, and
a messaging engine is configured for that cluster, any of the servers in that
cluster can handle work items for the messaging engine. The default message
provider in WebSphere Application Server is based on Service Integration Bus
(SIB) technology, and is governed by the Default SIBus policy, which is a
One of N policy. This policy ensures that only one of the application servers
in the cluster is active at a time). You can modify the high availability
group policy to specify that a specific cluster member handles the messaging
work.
Before you begin
Before specifying a preferred server for messaging requests:
- You should review the following topics:
- You must determine:
- The name of the core group that includes the server that you want to handle
messaging requests.
- The name of the high availability group for the messaging function.
- The name of the policy that is associated with this high availability
group
- You must create a new policy specific to the high availability group that
controls the messaging engine cluster, if one does not already exist.
It
is possible for a single policy to govern several different high availability
groups. Therefore, to modify the policy for cluster scoped control, you must
create a new policy specific to the high availability group that controls
the messaging engine cluster. See Creating a policy for a high availability group
for
more information on how to create this policy.
After you create the
new policy and associate the policy with the high availability group for a
given cluster, You can specify a preferred server for messaging requestws..
About this task
For high availability, you must configure a messaging engine to run
in a cluster. However, you might want a specific cluster member to handle
the messaging requests. Another member of the cluster should handle the messaging
requests only if the preferred member fails.
Procedure
- In the administrative console, click Servers > Core groups >
Core group settings > core_group_name.
- Click the Runtime tab to determine both the name of the
high availability group, and the name of the policy that is currently controlling
the group. See Viewing high availability group information
for
more information on how to perform this step. You must have at least one of
the group members running.
- In the administrative console, click Servers > Core groups >
Core group settings > core_group_name > Policies.
- Click the name of the policy that you want to modify.
- Under Additional Properties, select Preferred servers and
select the preferred servers for this policy.
Click Add to
move core group servers into the list of preferred servers.
Select
specific servers in the list and click Move up and Move down to
adjust the order of the servers within the list. Make sure that the most preferred
server is at the beginning of the list and the least preferred server is at
the end of the list.
- After you complete the preferred servers list, click OK.
- Click OK, and then click Save to
save your changes.
- Select Synchronize changes with nodes,
and then click Save again.
Results
All work items for the messaging engine on the associated cluster
are routed to the new preferred server.