Cluster-Wide Configuration Changes Oracle BI EE High Availability Concepts

15-16 Oracle Fusion Middleware High Availability Guide

15.1.2.3 Starting and Stopping the Cluster

Because there are dependencies between the processes, you must start a cluster in a particular order. The startup sequence is:

1. Start all of the WebLogic Managed Servers. The system components look to their

local Managed Server for the authentication service.

2. Start other processes using the Start All button in Fusion Middleware Control.

Using the Start All button ensures that the Java applications and the system components start in the correct startup order.

15.1.2.4 Cluster-Wide Configuration Changes

Configuration changes, especially changes to the population of the cluster, are critical for high availability. Without the ability to add new members to a cluster, a failure cannot be repaired, leaving the cluster vulnerable to a subsequent failure this is why mean time to repair is just as important in a high availability system as mean time between individual failures. The two technology stacks, Java and system, are managed separately. WebLogic configuration changes are made in the WebLogic Administration Console. Standard WebLogic mechanisms are used to lock configuration while it is being changed, and to propagate the changes to all Managed Servers. System component configuration changes are made centrally using Fusion Middleware Control. After you enter configuration changes and click Save, the configuration changes propagate to all local configuration files. This propagation is important; if the configuration is corrupt or propagation fails, the next propagation corrects the local files. An Oracle JMX extension performs file distribution similar to the WebLogic config file distribution. Delivery at the remote site is announced by a JMX MBean call. Since MBeans must be hosted in an MBean server, this means that every machine which hosts Oracle BI EE system components must also have a WebLogic Managed Server even if that machine does not host any Java Oracle BI EE components. All components access configuration changes at their next restart only; there is no online configuration reload mechanism. Configuration changes are triggered by: ■ An administrator committing changes made in the Fusion Middleware Control. ■ An administrator committing changes made by the MBeans API which directly mirrors the Fusion Middleware Control user interface. An enterprise installation that registers a new installation does not trigger a configuration push. This changes the population of machines which the administrator may pick from in the Fusion Middleware Control - new component instances are not automatically added to the configuration.

15.1.2.5 Protection From Failures and Expected Behaviors