Configuring the core group bridge between core groups that are in different cells

The core group bridge service can be configured for communication between core groups. Use an access point group to define the core groups that communicate. Use this task to configure communication between core groups that are in different cells.

Before you begin

Make sure that:
  • You have two or more core groups that are in different cells. Core groups are a statically defined component of the high availability manager.
  • Any cell that uses core group bridges to connect to core groups in other cells have a name that is unique when compared to the names of the other cells.
  • Any core group that uses a core group bridge is configured with Channel framework as its transport mechanism.

About this task

Use the core group bridge service to share the availability status of the servers in each core group among all the configured core groups. Enable the core group bridge only when the service is required by a WebSphere Application Server component.

When you configure core group communication between core groups that are in different cells, you must configure an access point group to connect the core groups. The name of the access point group must be the same in all of the connected cells. This task uses the DefaultAccessPointGroup access point group, but you can create and use another access point group.

Avoid trouble: When configuring core group bridges, remember the following requirements:
  • Whenever a change is made in core group bridge configuration, including the addition of a new bridge, or the removal of an existing bridge, you must fully shutdown, and then restart all core group bridges in the affected access point groups.
  • There must be at least one running core group bridge in each core group. If you configure two bridges in each core group, a single server failure does not disrupt the bridge functionality. Also, configuring two bridges enables you to periodically cycle out one of the bridges. If all the core group bridges in a core group are shutdown, the core group state from all foreign core groups is lost.
gotcha
Best practice: It is also recommended that:
  • Core group bridges be configured in their own dedicated server process, and that these processes have their monitoring policy set for automatic restart.
  • For each of your core groups, you set the IBM_CS_WIRE_FORMAT_VERSION core group custom property to the highest value that is supported on your environment.
  • To conserve resources, do not create more than two core group bridge interfaces when you define a core group access point. You can use one interface for workload purposes and another interface for high availability. Ensure that these interfaces are on different nodes for high availability purposes. For more information, see the frequently asked question information on core group bridges.
bprac

Complete the following set of steps for each of the cells in your configuration.

Procedure

  1. Configure bridge interfaces for your core group access point. Configuring a bridge interface indicates that the specified node, server, and chain combination is a core group bridge server. This node and server use the specified chain to communicate with other core groups.
    1. In the administrative console, click Servers > Core groups > Core group bridge settings > Access point groups > DefaultAccessPointGroup > Core group access points > CGAP_1\DefaultCoreGroup > Show detail > Bridge interfaces > New.
    2. Select a node, server, and transport channel chain that becomes your bridge interface.
    3. Click Apply.
    4. Repeat this set of steps to add more bridge interfaces to the core group access point. Define at least two bridge interfaces for each core group access point to back up your configuration. By defining two bridge interfaces, you define two core group bridge servers. If one core group bridge server fails, the other can take over the work so that the communication between the core groups can continue.
      Important:
      The bridge interfaces that you select must all have the same transport channel chain.
  2. Add peer access points and peer ports to your access point group.
    Add a peer access point for each core group that is in another cell. Within each peer access point, you should configure a peer port that corresponds to each bridge interface in the other cell. Before you add a peer access point, you should have the following information about the other cell:
    • cell name
    • core group name
    • core group access point name
    • host and port information. The host and port correspond to the bridge interfaces that are configured in the other cell. Specify a peer port for each bridge interface that is in the other cell.
    1. In the administrative console, click Servers > Core groups > Core group bridge settings > Access point groups > DefaultAccessPointGroup > Peer access points > New.
    2. Specify the information for your peer access point and click Next.
    3. Select Use peer ports. Specify the host and port information for your peer cell. For example, if you defined a bridge interface in cell_x, use that configuration information for your peer port in cell_y.
    4. Click Next and then Finish. Save your configuration.
    If more than one bridge interface is defined in your peer cell, add additional peer ports for each bridge interface.
    1. Click Peer_access_point_name > Show detail > Peer ports > New.
    2. Enter the host name and port.
    3. Click Apply and save your changes.
  3. Optional: Configure the high availability manager protocol to establish transparent bridge failover support.

    During core group bridge state rebuilds, cross-core group state can be moved between running bridges. This situation might cause the data to be temporarily unavailable until the bridge has completed the rebuild process.

    If you are running on Version 6.0.2.31 or later, set the IBM_CS_HAM_PROTOCOL_VERSION core group custom property to 6.0.2.31 for all of your core groups to avoid a possible high availability state outage during core group bridge failover. When this custom property is set to 6.0.2.31, the remaining bridges recover the high availability state of the failed bridge without the data being unavailable in the local core group.

    Complete the following actions to set the IBM_CS_HAM_PROTOCOL_VERSION core group custom property to 6.0.2.31 for all of your core groups.

    1. Shut down all core group bridges in all of your core groups.
    2. Repeat the following actions for each core group in each of your cells:
      1. In the administrative console, click Servers > Core Groups > Core group settings > core_group_name > Custom properties.
      2. Specify IBM_CS_HAM_PROTOCOL_VERSION in the Name field, and 6.0.2.31 in the Value field.
      3. Save your changes.
    3. Synchronize your changes across the topology.
    4. Restart all of the bridges in the topology.
    All of the core groups within this topology are using the 6.0.2.31 high availability manager protocol.

Results

You configured the core group bridge between core groups that are in different cells.

Example

The following illustration is an example of a configuration between two core groups that are in two different cells. Each cell has a defined DefaultAccessPointGroup access point group, which contains one core group access point for the core group that is in the cell and a peer access point for the other cell.

What to do next

Continue configuring the high availability environment.



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Last updated: Sep 20, 2010 10:03:57 PM CDT
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