File name: urun_rwlm_cluster_create2_v61.htmlCreating 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 .
- 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 cluster_name.
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.
|
