### Managing the predefined server list

#### Predefined server list

A predefined server list, which is stored in the server.list file, is a list that records relevant information about the clustered servers. The information includes server name, server IP address, server RMI port, and server backup priority.

The predefined server list is used for two main purposes:

- To determine the priority for a backup server to switch the role to run as the admin server when the server is shut down or has crashed.

  In a clustered environment, there can be more than one backup server. When the admin server fails to function, one of the backup servers will promote itself to run as the admin server. Which backup server should do this is determined by the backup priority settings defined in the server.list file (the jrs.cluster.server.backup.priority property).

- To monitor the status of the servers in the cluster.

  JReport Server Monitor can monitor the clustered server status and allows you to perform some administrative tasks. However, only when a server is added to the predefined server list, can it be tracked and monitored by JReport Server Monitor.

#### Managing predefined server list

If in the server.properties file, the property cluster.only_accept_predefined_server is set to true, then before a server can join the cluster, it must first be included in the predefined server list. If you log onto the admin server as an administrator, you can manage the cluster server list in the Predefined Server List.

- To display the predefined server list:
  1. On the JReport Administration page, click Cluster on the system toolbar.
  2. Click the Config tab, then the predefined server list will be displayed.
- To add a server to the list:
  1. In the Config tab, click the Add Server link.
  2. In the Add Predefined Server dialog, supply relevant information about the server: Server Name, Host Address, RMI Port, and Backup Priority.
  3. When done, click OK and the server will then be added to the Predefined Server List table.
- To remove a server from the list, click the corresponding Delete link.

Notes:

- The backup priority for each backup server cannot be the same, but can be left empty. The default priority for the admin server is 0, which is the highest level of priority in the cluster.
- If the server you are adding is a backup server, you must specify a backup priority for it. Otherwise, it will be considered as a slave server and will never be promoted to be an admin server.
- If the server you are adding is a slave server, leave the backup priority field empty. The cluster will not recognize a specified backup priority for a slave server.
- The name of the server you are adding is only used by JReport Enterprise Server. It does not need to be the same as the host name of the computer where the server runs. The specified Host Address is used to locate the computer in the network.