The file synchronization service

WebSphere Application Server Network Deployment uses the file synchronization service to ensure that configuration and applications are consistent for all of the application servers in a Network Deployment cell. File synchronization copies files from the deployment manager to the nodes, and then from the nodes to the application servers. Files are not copied from individual application servers or nodes to the deployment manager. Configuration and application updates should always be made in the deployment manager. Any changes that you make at the node or application server level are overwritten the next time the synchronization service runs.

When you make changes to the configuration of a managed node, it is recommended that you synchronize the configuration with managed nodes. If you do not synchronize the configurations, the nodes use their previous configurations until the next synchronization occurs. You can configure the node agent for a managed node to request configuration synchronization automatically, or you can send a request from the deployment manager to the node agent to synchronize the configurations. By default the node agent is configured to synchronize with the deployment manager every minute.

The synchronization service uses the file transfer service to copy configurations and applications from the deployment manager to the nodes. In WebSphere Application Server Network Deployment, Version 5.0.1, the file transfer service provides role-based authentication. The Version 5.0.1 PTF includes two versions of the file transfer Web application:

• The unsecured version is located in the /QIBM/ProdData/WebAS5/ND/installableApps/filetransfer.ear file. This file is the same version that ships with WebSphere Application Server Network Deployment, Version 5.0.
• The secured version is located in the /QIBM/ProdData/WebAS5/ND/installableApps/filetransferSecured.ear file.

By default, the unsecured version is installed. After you upgrade all of the application servers in your Network Deployment cell to WebSphere Application Server Network Deployment, Version 5.0.1, you can deploy the secured version of the file transfer service. You can run the redeployFileTransfer.jacl script in wsadmin to redeploy the file transfer application. The script is located in the /QIBM/ProdData/WebAS5/ND/bin directory. For information on deploying the secured file transfer application, see Enable authentication in the file transfer service. For information on running wsadmin, see The wsadmin administrative tool.

This list describes the file synchronization service in more detail:

• File synchronization can run automatically and by request.
  By default, the automatic file synchronization service is enabled and is set to run every minute. Use the administrative tools to enable, disable, and configure the automatic file synchronization service for the cell. For more information, see File synchronization service settings.

  You can also use any of these methods to run file synchronization manually:

  • Run the syncNode script for the node that you want to synchronize.
  • Use the Network Deployment administrative console to manually synchronize a node.
  • When you save changes in the Network Deployment administrative console, the change can be propogated to all nodes. See Save the configuration for more information.

• They synchronization service only updates files that have changed.
  Epochs are used to determine if a file has changed since the previous synchronization. If you manually edit a file instead of using the administrative tools the server does not recognize that the file has changed. In this case, use the administrative console to perform a full resynchronization. When you perform a full resynchronization, the application server compares all of the files and synchronized the changed files. The syncNode script does not support full resynchronization.

• The file synchronization service manages configuration information and applications.
  To specify whether an application is included in synchronization, select the Enable Distribution attribute for the application. See the Provide options to perform the installation step in Install and uninstall applications for information about this attribute. You can also use the administrative console to enable distribution after the application is installed. See Enterprise application settings for more information.

  If distribution is enabled for the application, the synchronization service copies the application EAR file from the cell repository to each node in the cell. The EAR file is expanded in the node's local file system at the location specified in the binariesURL for the application. The binariesURL is specified in the application's deployment.xml file.

• You can configure the file synchronization service to exclude some files when it runs.
  An excluded file is identified by its URI in the cell repository. The path is relative to instance/config, where instance is the name of your instance. For example, if your instance is named myInstance, and you specify myFile.xml in the exclusion list, the synchronization service excludes the document named myFile.xml in the /QIBM/UserData/WebAS5/ND/myInstance/config directory. If you specify cells/myCell/myFile.xml, the synchronization service excludes the document named myFile.xml in the /QIBM/UserData/WebAS5/ND/myInstance/config/cells/myCell directory. The sync service also recognizes a simple pattern matching scheme for exclusions. Use an asterisk (*) as a leading or trailing wildcard character. For example, */myFile.xml excludes all documents named myFile.xml that are located in the /QIBM/UserData/WebAS5/ND/myInstance/config directory and any of its subdirectories, and cells/myCell/myDir/* excludes the entire subtree under the myDir directory.

  Note: In versions 5.0.1 and later, WebSphere Application Server for iSeries automatically includes the plugin-cfg.xml file on the exclusion list. See Regenerate the plugin configuration for a federated node for more information.