Dynamic cluster settings

Use this page to view configurations of existing dynamic clusters.

To view this administrative console page, click Servers > Dynamic clusters > dynamic_cluster_name .

You must have monitor privileges to view the configuration of existing dynamic clusters.

Name

Specifies a name for the dynamic cluster. The name for a dynamic cluster must be unique among all the clusters in the cell.

The name field cannot contain the following characters: # \ / , : ; " * ? < > | = + & % ' . The name cannot begin with a period (.) or a space. A space does not generate an error, but leading and trailing spaces are automatically deleted.

Type

Specifies the type of servers that are being used in the dynamic cluster.

The following list contains the server types:

WebSphere Application Server
Specifies that the dynamic cluster contains application servers that are running WebSphere Application Server or WebSphere Virtual Enterprise.
Apache server
Specifies that the dynamic cluster contains Apache servers.
Custom HTTP server
Specifies that the dynamic cluster contains HTTP servers.
JBoss server
Specifies that the dynamic cluster contains servers that are running JBoss Application Server.
On demand router
Specifies that a dynamic cluster of on demand routers is being created.
PHP server
Specifies that the dynamic cluster contains servers that are running PHP.
Apache Tomcat server
Specifies that the dynamic cluster contains servers that are running Apache Tomcat.
WebSphere Application Server Community Edition server
Specifies that the dynamic cluster contains servers that are running WebSphere Application Server Community Edition.
BEA WebLogic server
Specifies that the dynamic cluster contains servers that are running BEA WebLogic.
External WebSphere application servers
Specifies that the dynamic cluster contains servers that are in other cells. These cells might be running other versions of WebSphere Application Server, such as Version 5.1 or 6.0. You can map these static clusters to a dynamic cluster.
Number of running instances

Specifies an automatically generated value that is based on the number of server instances that are running for the dynamic cluster.

For example, a dynamic cluster might have three applications running, with two instances running on each of the four members of the dynamic cluster. The number of instances is 8.

Operational mode

Specifies the level that the dynamic cluster interacts with the dynamic operations environment:

  • Manual: In manual mode, the dynamic cluster is no different than the normal application server environments with static clusters. No interaction with the dynamic operations environment occurs.
  • Supervised: In supervised mode, the WebSphere Virtual Enterprise environment provides information and recommendations for actions that the administrator can use.
  • Automatic: In automatic mode, the WebSphere Virtual Enterprise environment takes actions automatically. In automatic mode, the dynamic operations environment handles placements and provisioning.

You can change the operational mode in the administrative console by clicking Server > Dynamic clusters.

Enable failover of transaction log recovery

Specifies that for the transaction service component, failover of the transaction log for recovery purposes is enabled or disabled. This field is valid for WebSphere application server dynamic clusters only.

The default is disabled. If you enable this setting, the transaction service properties that are required for peer recovery of failed applications must be properly configured. If these properties are configured, failover recovery of the transaction log occurs if the server processing the transaction log fails. If the transaction services properties that are required for peer recovery of failed application servers in a cluster are not properly configured, this setting is ignored.

Membership policy

Specifies an expression that is used to define which nodes are used for the dynamic cluster. This option displays only if you choose to automatically define cluster members with rules. This option does not display if you choose to manually define your cluster members.

Use the subexpression builder to build a Membership policy. The membership policy specifies which nodes are members of the dynamic cluster. Click Preview membership to view which nodes are in the dynamic cluster with the membership policy that you defined.

Example

  • To define membership as all nodes in a specific node group:
    node_nodegroup = 'my_node_group'
  • To define membership as all nodes that run Apache:
    node_property$APACHE_2_0 IS NOT NULL
  • To define membership as all nodes that run Apache and PHP:
    node_property$APACHE IS NOT NULL and node_property$PHP IS NOT NULL
  • To define membership as all nodes that run WebSphere Application Server Community Edition Version 2.0 or later:
    node_property$WASCE_2.0* IS NOT NULL
  • To define membership as all nodes that run WebSphere Application Server Community Edition Version 2.0 only:
    node_property$WASCE_2.0 IS NOT NULL
  • To define membership as all nodes that have a name that is like my_node, including my_node_1, my_node_2, and so on:
    node_name like 'my_node%'
  • To define membership as a list of specific host names:
    node_hostname in ('node1.mydomain.com','node2.mydomain.com')
You can group subexpressions by using and, or, or not logical operators and parenthesis. The following example defines node membership as nodes that are not in the my_node_group node group, and have a name that is like my_node, including my_node_1, my_node_2, and so on.
not (node_nodegroup='my_node_group') and node_name like 'my_node%'
Minimum number of cluster instances

Specifies the minimum number of running instances for the dynamic cluster. If a minimum value is excessive, performance degradation might occur.

  • If you want to stop instances when no activity exists, click Stop all instances during periods of inactivity. If you select this option, enter the Time to wait before stopping instances value in minutes.
    Restriction: If you are routing Session Initiation Protocol (SIP) traffic to the dynamic cluster, do not use the If other dynamic clusters need resources, stop all instances of this cluster during periods of inactivity option. Use one of the options that keep at least one cluster member active at all times.
  • If you want one cluster instance started at all times, click Keep one instance started at all times. This option is the default.
  • If you want more than one cluster instance started at all times, click Keep multiple instances started at all times. If you select this option, enter the Number of instances that you want started at all times.
Maximum number of cluster instances

Specifies the maximum number of cluster instances that can start.

  • If you want to limit the number of cluster instances, click Limit the number of instances that can start, and enter the maximum Number of instances.
  • If you do not want to limit the number of cluster instances, click Do not limit the number of instances that can start.
Vertical stacking of instances on a node

Specifies if more than one instance can start on a single node. By configuring vertical stacking, the application placement controller can start more than one instance of the dynamic cluster on the node when a large workload exists.

Use vertical stacking to improve bottleneck conditions between applications. Select Allow more than one instance to start on the same node, and type the Number of instances value. The number of instances is the number of application servers for a cluster that are needed to use all the power of a node. Also, the number you choose for vertical stacking is the number of servers that are automatically created.

If you use target nodes for vertical stacking that are at an older product version than the deployment manager version, adding new members on the same node is disabled. Vertical stacking is available only on application servers, WebSphere Application Server Community Edition servers, and PHP servers that have cluster members that are automatically defined by rules.

Isolation preference

Specifies if you want the dynamic cluster to run on the same nodes as other instances of dynamic clusters, or if you want the dynamic cluster to be the only dynamic cluster that is running on a node. This option is available if you choose to automatically define your cluster members with rules. If you manually define your cluster members, you do not have the option to enable dynamic cluster isolation.

  • Select No isolation requirements if cluster instances in this dynamic cluster can run on the same node as other instances from different dynamic clusters. This option is the default.
  • Select Strict isolation if cluster instances in this dynamic cluster can run only with other instances of the same dynamic cluster on the same node.
  • Select Associate with an isolation group if the cluster instance can run with any other instance of a dynamic cluster that is in the same shared group on the same node. Specify an Isolation group name value. To create a new isolation group for this dynamic cluster, type a unique name. To select from a list of the existing isolation groups, click Browse. A topology of the current isolation groups is displayed. Click an isolation group name to select the group.



WebSphere Virtual Enterprise information center (online)

Related information
Dynamic cluster collection
Membership policy builder
Step 1: Select the dynamic cluster server type
Step 2: Select a membership method
Step 3: Define the dynamic cluster members
Step 4: Select a server template
Step 5: Configure the dynamic cluster properties
Step 6: Summary
Dynamic cluster member collection
Dynamic cluster member settings

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