Installation Recommendations for All Migrations

The most apparent difference in version 8.1 is that the domain directory structure lies outside the WebLogic Server installation. When migrating existing domains, it's recommended to take advantage of the new structure by placing it outside of the WebLogic Server installation directory as well. If you create a new domain in version 8.1 using the Configuration Wizard utility, the default output destination is a \user_projects directory that's located outside of the WebLogic Server installation. You are, however, encouraged to create your own structure. The independent structure allows for greater maintainability and flexibility. For instance, you could create separate directories for development, test, and production.

In addition, it's recommended to separate the roles and responsibilities of the administrative server and managed servers. This model was first introduced in version 6.0, and version 7 introduces a new deployment process and staging modes that further support that model. Version 8.1 builds on top of the new approach from version 7.

The distributed model is to use the administrative server for administrative purposes and to deploy applications on the managed servers. Even if the administrative and managed servers are running on the same machine, there are advantages to maintenance as well as the instant capability to scale or join a cluster. WebLogic goes on to support this model further in version 8 with its two-phase deployment. When you deployed an application in version 6.0/6.1/7.0, a copy was sent and deployed on all the target servers. If deployment on one of those servers failed, the application would be placed in an inconsistent state. Version 8.1 helps prevent this from happening by splitting deployment into two phases, and it works much like a transaction's two-phase commit:

Prepare phase— A copy of the application is sent to all target servers and loaded, but clients cannot yet access the application.
Activation phase— If all the servers respond that they've successfully received and loaded the application, they then activate, which allows client access.

If you've moved the application to your managed servers, the two-phase deployment process assures you that the application is deployed and active on all targeted servers. This was introduced in WebLogic 7.0 and enhanced in WebLogic 8.1.

Moving applications to managed servers also enables you to take advantage of version 8.1's application staging modes. By defining a staging mode, you can control how files are copied for deployment. For more information about application staging, refer to the BEA documentation at http://edocs.bea.com/wls/docs81/deployment/index.html and Chapter 7, "Deploying Web Applications."

The last major change you might want to implement is to upgrade security. If you upgraded from version 4.5/5.1, the conversion utility converted the security information from the weblogic.properties file into a file-based WebLogic Server 6.1–type format (in the fileRealm.properties file). When an upgraded domain with file-based security is started in version 8.1, it runs in compatibility mode security. This security level might be fine for your present operation, but you might want to upgrade to WebLogic Server 8.1 security to take advantage of its improved security features, such as JAAS authentication. We showed you earlier in this appendix how to upgrade from compatibility mode security to WebLogic Server 8.1 security.

[ Team LiB ]