WebSphere Extended Deployment, Version 6.0.x
             Operating Systems: AIX, HP-UX, Linux, Solaris, Windows, z/OS


Configuring the on demand router for multi-cluster failover and load balancing routing

To configure the on demand router (ODR) to route requests to a different cluster, you can configure custom properties for configuring multi-cluster failover and load balancing routing policies. You might route requests to a cluster in another cell if your primary cluster fails, to balance the load in your environment between multiple clusters, or to direct the ODR to route requests to a specific cluster.

Before you begin

Create the ODR for your cell. Configure and deploy the clusters and applications for your multi-cluster policy.

About this task

Use multi-cluster routing policies for failover and load balancing. With failover, you can specify a cluster to take over the workload when the primary cluster fails. With load balancing routing, you can balance the request loads between multiple clusters.

Procedure

  1. Create a custom property for the multi-cluster routing policy. In the administrative console, click Servers > On demand routers > ODR_name > On demand router properties > On demand router settings > Custom properties > New.
  2. Type a name for the multi-cluster routing policy in the Name field. The name must start with the token MCRP@ string. The full syntax of the name field follows:
    MCRP@<cell_name>[$<application_name>[$<web_module_name>]]
    The following table defines the components of the name field syntax:
    Option Description
    MCRP Specifies that the custom property is a multi-cluster routing policy (MCRP). This prefix must be specified in uppercase letters.
    @ Required symbol. This symbol is the separator between the policy name and the cell. In this configuration, it is generally used to separate a policy name attribute from a cell name.
    cell_name Specifies the name of the cell. This cell must be a valid cell that runs WebSphere® Application Server. The case and spelling must match the way that you created the cell in WebSphere Application Server.
    $ Separates the WebSphere Application Server objects.
    application_name Specifies the application name without the file extension. For example, if the enterprise application name is StockTrade.ear, then specify StockTrade as the application_name value.
    web_module_name Specifies the name of the Web module without the .war file extension.
    [ ] Indicates variables that are optional.
  3. Type a value in the Value field. The full syntax of the value field follows:
    <policy_type>@<cell_name1>$<cluster_name1>[,<cell_name2>$<cluster_name2>,...]
    The following table defines the components of the value field syntax:
    Option Description
    policy_type Valid values:

    failover: When a request for the application web module in the cell that is specified in the Name field fails, the request fails over to the cell and cluster that are specified in the Value field after the @ symbol. Requests only route to the configured cell and cluster when the primary cell is down. The cell status is signified by an HTTP status code of 503, service unavailable. New weight values are obtained every 15 seconds from the Dynamic Work Load Manager (DWLM), which takes into account the application level response time. Use the mcrp.ui system property to set the new update time in seconds.

    wlor: Specifies a weighted least outstanding request load balancing policy. This policy comes into effect when the ODR is active and reads its custom property configuration.

    wrr: Specifies a weighted round-robin load balancing policy. This policy comes into effect when the ODR is active and reads its custom property configuration.

    The policy_type value is not case sensitive. The failover, wlor, or wrr values can be specified in uppercase or lowercase.

    cell_name Specifies the name of the cell. This cell must be a valid cell that runs WebSphere Application Server. The case and spelling must match the way that you created the cell in WebSphere Application Server.
    cluster_name

    The cluster name values that are used in the value field must be generic server cluster names, because the ODR MCRP routing to a remote cell is achieved without compromising security concerns or the need to configure cross-cell communication by using the generic server cluster implementation. While the cell on the policyType can be the same as the primary cell (cell specified in the Name field), the cluster name must be a generic server cluster name. MCRP routing also maintains established session affinity.

    The cluster name value must be capitalized and spelled the same way that you specified the name when you created the cluster in the administrative console.

    , The comma (,) is used to separate a set of values in the list.

    All Java™ 2 Platform Enterprise Edition (J2EE) artifact names such as cell_name, application_name, and cluster_name must be spelled the way that they were created and deployed in WebSphere Application Server.

    A few examples for the value field follow:

    failover@thesaharaCell01$myGSC1
    wlor@thesaharaCell01$myLondonGSC
    wrr@thesaharaCell01$myNYCGSC
  4. Type some optional text in the Description field.
  5. Click Apply or OK to commit your new custom settings.

Results

The ODR routes to multiple clusters, as you configured in the multi-cluster routing policy.

What to do next

You might want to configure the ODR to route work to nodes that are not running WebSphere Extended Deployment. After you create the ODR and apply any optional configuration parameters, you can define the ability to route work to non-Extended Deployment nodes.




Related tasks
Creating ODRs
Configuring WebSphere Extended Deployment for cross-cell communication
Related reference
Creating and deleting on demand routers with scripts
Related information
Proxy server settings
Task topic    

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Last updated: Nov 30, 2007 3:58:31 PM EST
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