Configuring WebSphere Application Server HTTP session persistence to a data grid

Configure your WebSphere® Application Server application to use the appliance for session management. You can either select the appliance when you are installing a new application, or you can update your existing application or server settings to use the appliance.

Before you begin

Before you change the configuration in WebSphere Application Server, you must have:

Access to the WebSphere Application Server cell that you want to configure.
The IP address or fully qualified host name of the appliance.
A user ID and password that you use to log in to the appliance user interface. To create a data grid, you must have data cache creation permissions.
WebSphere eXtreme Scale Client installed in your WebSphere Application Server configuration. For more information, see Installing WebSphere eXtreme Scale Client.
Global security that is enabled in the WebSphere Application Server administrative console. Enable global security if your appliance has transport layer security that is enabled, or you want to ensure that clients use transport layer security. For more information, see Configuring Transport Layer Security (TLS) for WebSphere Application Server.
(optional) Create a session data grid in the user interface. For more information, see Creating session data grids.

Procedure

To configure session management when you are installing the application, complete the following steps:
1. In the WebSphere Application Server administrative console, click Applications > New application > New Enterprise Application. Choose the Detailed path for creating the application and complete the initial wizard steps.
2. In the eXtreme Scale session management settings step of the wizard, configure the data grid that you want to use. For the Manage session persistence by field, choose WebSphere DataPower XC10 Appliance. Enter the information about the appliance and the data grid on the appliance that you want to use. You can either create a data grid or use an existing data grid that you already configured on the appliance.
3. Complete the wizard steps to finish installing your application.
You can also install the application with a wsadmin script. In the following example, the -SessionManagement parameter creates the same configuration that you can in the administrative console:
```
AdminApp.install('C:/A.ear', '[  -nopreCompileJSPs -distributeApp 
-nouseMetaDataFromBinary -nodeployejb -appname A -edition 8.0 
-createMBeansForResources -noreloadEnabled -nodeployws -validateinstall 
off -noprocessEmbeddedConfig -filepermission .*\.dll=755#.*\.so=755#.*\.a=755#.*\.sl=755 
-buildVersion Unknown -noallowDispatchRemoteInclude -noallowServiceRemoteInclude 
-asyncRequestDispatchType DISABLED -nouseAutoLink  -SessionManagement [[true 
XC10SessionManagement myXC10.ibm.com:!:username:!:password:!:AGrid80]]  
-MapWebModToVH [[MicroWebApp microwebapp.war,WEB-INF/web.xml default_host] [MicroSipApp 
microsipapp.war,WEB-INF/web.xml default_host] [MicroDG1App microdg1app.war,WEB-INF/web.xml 
default_host] [MicroDG2App microdg2app.war,WEB-INF/web.xml default_host] [MicroSip2App 
microsip2app.war,WEB-INF/web.xml default_host]]]')
```
To configure session management on an existing application in the WebSphere Application Server administrative console:
Note: The Override session management box is checked when the application is set to use WebSphere DataPower XC10 Appliance. This means any server level session settings that were made to WebSphere Application Server configuration are overwritten by the application-level session settings. If you do not want to override settings, you can enable WebSphere DataPower XC10 Appliance at the server level.
1. In the WebSphere Application Server administrative console, click Applications > Application Types > WebSphere enterprise applications > application_name > Web Module properties > Session management > eXtreme Scale session management settings.
2. Update the fields to enable session persistence to a data grid.
You can also update the application with a wsadmin script. In the following example, the -SessionManagement parameter creates the same configuration that you can in the administrative console:
```
AdminApp.edit('A-edition9.0', '[ -SessionManagement [[true 
XC10SessionManagement myXC10.ibm.com:!:username:!:password:!:AGrid80]]]')
```
The :!: characters that are passed are used as delimiters. The values that are passed are:
```
applicationIdentifier:!:username:!:password:!:
gridName
```
When you save the changes, the application uses the configured data grid for session persistence on the appliance.
To configure session management on an existing server:
1. In the WebSphere Application Server administrative console, click Servers > Server Types > WebSphere application servers > server_name > Session management > eXtreme Scale session management settings.
2. Update the fields to enable session persistence.
You can also configure session management on an existing server with the following wsadmin tool commands:
```
AdminTask.configureServerSessionManagement('[-nodeName my_node 
-serverName server1 -enableSessionManagement true -sessionManagementType 
XC10SessionManagement -XC10SessionManagement [-applianceIdentifier myserver.ibm.com 
-userName -password ******** -gridName myTestGrid]]')
```
When you save the changes, the server now uses the configured data grid for session persistence with any applications that are running on the server.

Results

You configured HTTP session manager to persist the sessions to a data grid. Entries are removed from the data grid when the sessions time out. See Session management settings for more information about updating the session timeout value in the WebSphere Application Server administrative console.

If the entire data grid that is hosting the application session data is unreachable from the web container client, the client instead uses the base web container in WebSphere Application Server for session management. The data grid might be unreachable in the following scenarios:

A network problem between the Web container and the appliance.
The server processes on the appliance have been stopped.

The least recently used sessions are invalidated from the web container session cache. If the data grid on the appliance becomes available, sessions that were invalidated from the web container cache can retrieve data from the remote data grid and load the data into a new session. If the entire data grid on the appliance is not available and the session is invalidated from the session cache, the user session data is lost. Because of this issue, do not shut down entire production data grid when the system is running under load.

CAUTION:

When you configure this scenario, the security credentials for the IBM WebSphere DataPower XC10 Appliance are automatically stored in the WebSphere Application Server configuration. If you change the credentials for the data grid after the initial configuration, the WebSphere Application Server no longer has the correct credentials. You can reset the credentials by applying the eXtreme Scale session management settings again.

What to do next

Configure security before you begin to send data to the data grid. See Enabling security for data grids for more information.
Configure replicas. Replicas ensure that your data grid data is available if the primary copy fails. To configure replicas, click Data Grid > Session > Show advanced attributes. Replicas are created only when the appliance is in a collective. If the number of appliances in the collective is n, the maximum number of replicas is n-1. Therefore if you configure three replicas, but you only have two appliances in the collective, only one replica is created. Additional replicas are created if you add appliances to the collective. Set the number of replicas to the ideal amount that you want to have, so that as appliances join the collective, new replicas can be created. The data grid content is cleared when you edit the number of replicas.
Configure a capacity limit for the data grid. By configuring capacity limits on the data grid, you can ensure that the storage capacity for the collective is used in a predictable manner. See Configuring the maximum capacity of a data grid for more information.
Monitor your session data grid in the DataPower XC10 Appliance user interface. For more information, see Monitoring data grids in the user interface.