Creating a cluster: Create first cluster member

Use this page to specify settings for the first cluster member.

There are two ways to create the first member of a cluster:

You can create the first member when you create a cluster.
To create a cluster, in the administrative console, click Servers > Clusters > WebSphere application server clusters > New.
You can create an empty cluster and then add a first member after you finish creating the cluster.
To create a cluster member for an existing cluster, in the administrative console, click Servers > Clusters > WebSphere application server clusters > cluster_name > Clusters members > New.

When you create the first cluster member, a copy of that member is stored as part of the cluster data and becomes the template for all additional cluster members that you create.

When adding servers to a cluster, remember that the only way to remove an application server from a cluster is to delete the application server from the list of cluster members.

Member name

Specifies the name of the application server that is created for the cluster.

The member name must be unique on the selected node.

Select node

Specifies the node on which the application server resides.

Short name

Specifies the short name for this cluster member. This field only applies to the z/OS® platform.

The short name is the default z/OS job name and identifies the cluster member to the native facilities of the operating system, such as Workload Manager (WLM), Automatic Restart Manager, SAF (for example, RACF®), started task control, and others.

If you specify a short name for a cluster member, the name:

Must be one to eight characters in length. By default, WebSphere® Application Server for z/OS assumes that you are using a 7-character server short name (JOBNAME). If your naming standards require 8 characters, you can lengthen the 7-character server short name to 8 characters.
Must contain only uppercase alphanumeric characters
Cannot start with a number.
Must be unique in the cell
Cannot be the same as the value specified on the ClusterTransitionName custom property of any non-clustered server. Do not specify a cluster transition name for a server that is part of a cluster.

If you do not specify a short name, the system assigns a default short name that is automatically unique within the cell. You can change the generated short name to conform with your naming conventions.

Weight

Specifies the amount of work that is directed to the application server.

If the weight value for the server is greater than the weight values that are assigned to other servers in the cluster, the server receives a larger share of the cluster workload. The value can range from 0 to 20. Enter zero to indicate that you do not want requests to route to this application server unless this server is the only server that is available to receive requests.

On z/OS, weight is used to balance some of the workload types, but others are balanced by the z/OS system.

For HTTP requests, weights are used to distribute HTTP traffic between the web server plug-in and the controller handling the clustered application server. Assign a higher weight value to the application server that should receive the HTTP traffic.
For web services calls, information is transferred from a servant in one application server to a controller in another application server. The application server that receives the call has the highest weight value.
Weight has no affect on Internet Inter-ORB Protocol (IIOP) requests. IIOP requests are distributed to the correct application server using the sysplex distributor.

Core group

Specifies the core group in which the application server resides. This field displays only if you have multiple core groups configured. You can change this value only for the first cluster member.

Generate unique HTTP ports

Specifies that a unique HTTP port is generated for the application server. By generating unique HTTP ports for the application server, you avoid potential port collisions and configurations that are not valid.

Select how the server resources are promoted in the cluster

Specifies how resources such as data sources and schedulers are initially created in the cluster. Create settings at the cluster scope if the settings can be used across the entire cluster. Otherwise, create settings at the cluster member (server) level. Creating settings at the cluster scope reduces the amount of configuration that you maintain.

Attention: When you create a cluster, this setting is disabled if you select None. Create an empty cluster for the Select basis for first cluster member setting. Otherwise, this setting is enabled.

The list has the following options.

Cluster

Moves the resources of the first cluster member to the cluster level. The resources of the first cluster member replace the resources of the cluster. Move resources of the first cluster member when you want to promote the resources of a server to the cluster. Promoting resources is the recommended option.

The Cluster option is the default behavior in the administrative console.

Server

Maintains the server resources at the new cluster member level and does not change the cluster level resources.

The Server option is most useful in the following situations:

When you want different configuration settings for resources defined on each cluster member.
When you have deleted all of your cluster members and want to create new cluster members. However, you do not want to replace the cluster scoped resources when you create the cluster members.

Both

Copies the resources of the cluster member (server) to the cluster level. The resources of the first cluster member replace the resources of the cluster. The same resources exist at both the cluster and cluster member scopes.

Important: These options are available only for the first cluster member. All other members of a cluster are based on the cluster member template which is created from the first cluster member.

Select basis for first cluster member

Specifies the basis you want to use for the first cluster member.

If you select Create the member using an application server template, the settings for the new application server are identical to the settings of the application server template you select from the list of available templates.
If you select the defaultZOS template, which is the only one that is listed unless you used the createApplicationServerTemplate command for the AdminTask object to create additional templates, the first cluster member uses the default port assignments for the z/OS platform. If some of these ports are already defined for use elsewhere in your z/OS system, your newly created cluster member might not start, might function incorrectly, or might generate unexpected error messages. Therefore, you must resolve any port conflicts before you start this server.
If you select Create the member using an existing application server as a template, the settings for the new application server are identical to the settings of the application server you select from the list of existing application servers.
If you select Create the member by converting an existing application server, the application server you select from the list of available application servers becomes a member of this cluster.
If you select None. Create an empty cluster, a new cluster is created but it does not contain any cluster members.

Important: The basis options are available only for the first cluster member. All other members of a cluster are based on the cluster member template which is created from the first cluster member.