Setting up a high availability environment

The high availability framework that is provided with the product eliminates single points of failure and provides peer to peer failover for applications and processes running within the product environment. This infrastructure is managed by a high availability manager and includes cells, clusters, core groups, and high availability groups. Every high availability group has a policy associated with it that the high availability manager uses to determine which members of a high availability group are active at a given time.

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 environment.

About this task

The high availability manager is designed to function in all of the supported product topologies. However, a high availability-managed environment must comply with the following rules:

  • A cell in a high availability infrastructure is partitioned into one or more core groups. The product provides a default core group as part of the high availability manager function. You can use the administrative console to create additional core groups.
  • 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

  1. Enable the high availability manager if it is not already enabled.
  2. View information about the high availability groups, core groups, and core group members.
  3. Create a new policy and associate it with a high availability group.
  4. Change the policy that is associated with a high availability group.
  5. Create a new core group.
  6. Change the configuration settings for a core group.
    While running your applications in a highly available environment, you might want to move core group members to a different core group. You also might want to change one or more of the following:
  7. Configure a transport for a core group.
    If you are using an IIOP transport, you might also need to complete one or more of the following actions:
  8. Specify a core group when you add a node.
  9. Specify a core group when you create an application server.
  10. Set up a core group bridge.

    If you are using multiple core groups and members of different groups need to communicate with each other, you must set up a core group bridge to enable this communication.

  11. [z/OS]Set up a sysplex that is highly available.
  12. [z/OS]Control application rollout and workload routing in a high availability configuration.
  13. [z/OS]Manually update a high availability application.

What to do next

After you set up your product environment to comply with all of the high availability-managed environment rules, use the default core group to control this environment.

Avoid trouble: Do not add core groups unless you cannot properly perform without them. Also, do not change the default configurations unless doing so provides the solution to a specific problem. When you do make configuration changes, such as changing the policy for a high availability group or moving core group members between core groups, make sure you fully understand the effect such changes have on your entire environment. Such changes might affect application processing.

Read the topic High availability environment troubleshooting tips if you encounter problems while running applications in your high availability environment.