The application server infrastructure that is managed by a high
availability manager includes cells and clusters. These components relate
closely to core groups, high availability groups, and the policy that controls
the high availability infrastructure.
Before you begin
Plan out how you need to set up your high availability environment
to avoid the risk of a failure without failover coverage. As part of the planning
process, understand how the high availability manager can assist you in controlling
this type of an environment.
About this task
The high availability manager is designed to function in all of the
supported WebSphere Application Server topologies. However, a high availability-managed
environment must comply to the following rules:
- A cell in a high availability infrastructure is partitioned into one or
more core groups. WebSphere Application Server provides a default core group
as part of the high availability manager function. Additional core groups
can be created using the administrative console.
- A core group cannot extend beyond the boundaries of a cell, and it cannot
overlap with any other core groups.
- A cluster must be a member of only one core group. All of the individual
members of that cluster must be members of the same core group.
- Individual application servers are also members of a core group.
- All running members of a core group must be able to communicate with all
of the other running members of that same core group.
While administering your core groups, you might need to perform one
or more of the following tasks. These tasks can be performed in any order.
Procedure
- Set up preferred coordinators
- Change the number of core group coordinators.
- Configure a core group transport.
- Configure the discovery protocol for a core group.
- Configure the failure detection protocol for a core group.
- Configure a core group for replication
- Configure core group IP caching.
Set up IP addresses for high
availability manager communications for V6 and V6.0.1.
- Set up IP addresses for high availability
manager communications for V6.0.2 and higher.
- Configure core group socket buffers.
- Specify a core group when adding a node.
- Specify a core group when creating an application server.
- View the core groups contained in a cell.
- View the members of a core group.
- Create a new core group.
- Move core group members to a different core group.
- View high availability group information
- Create a new policy and associate it with a high availability group.
- Change the policy associated with a high availability group.
- Route high availability group work to a different server.
- Create core group access points, if you have multiple core groups
that need to communicate with each other.
- Control application rollout and workload routing
in a high availability configuration.
- Set up a high availability sysplex.
What to do next
Important: After you set up your WebSphere Application
Server environment to comply with all of the high availability-managed environment
rules, use the default core group to control this environment. DO NOT add
additional core groups unless your environment absolutely requires them. Also,
do not change the default configurations unless you are doing so to solve
a specific problem or situation. When you do make configuration changes, such
as changing the policy for a high availability group or moving core group
members between core groups in a multi-core group environment, make sure you
fully understand the effect such changes will have on your entire environment.
Troubleshoot any high availability environment problems
that might occur.