Overview

You can continue to provide Operational Decision Manager as a service while the software is being upgraded without shutting down the entire system. Each node is upgraded in turn, until all server nodes and all client nodes are upgraded. The rolling upgrade is complete when all components use the same version.

Scope

The rolling upgrade is available for the following Operational Decision Manager components:
  • Decision Server Rules
  • Decision Center
  • zRule Execution Server for z/OS®
Important: To perform the rolling upgrade, you must use the classic rule engine. The decision engine does not support the cross-version compatibility in V8.8.0.
Note: In-place upgrade of the following databases is not necessary when you perform a rolling upgrade from V8.7 to V8.8.0, since the database schemas are the same between these two versions:
  • Rule Execution Server database
  • Decision Warehouse database
  • Decision Center database

Cross-version compatibility

Operational Decision Manager provides a cross-version compatibility between two versions, Vn and Vn+1, where n represents a specific version. Cross-version compatibility allows two versions of runtime components and assets to coexist temporarily until they are upgraded to the same version.

Operational Decision Manager components are compatible with assets from an earlier version. That is, the assets such as RuleApps and rulesets that are generated in Vn can be used by the runtime components in Vn+1. However, components are not compatible with assets from a later version. The assets that are generated in Vn+1 cannot be used in the runtime components in Vn.

Restriction: Compatibility between Decision Center Vn and Decision Runner (SSP) Vn+1 is not guaranteed.
Important: Rule sessions and the linked execution units (XUs) must always be kept in the same version on the same JVM. A version mismatch might occur in a Java™ Platform, Enterprise Edition application server deployment, where the Decision Server components are independently deployed. The following components are deployed with a dependency to the XUs that are deployed as a resource adapter (RAR):
  • Rule Execution Server console
  • Scenario Service Provider (SSP)
  • Hosted transparent decision service (HTDS)
  • Rule Execution Server message-driven rule beans (MDB)
  • Rule Execution Server EJB sessions
  • Custom decision service embedding POJO rule sessions
All components that use the rule sessions in the Java Platform, Enterprise Edition application server must be deployed in the same version as the underlying XUs in the same application server.

This restriction applies to the Decision Server Java Platform, Enterprise Edition deployment, including WebSphere® Application Server Network Deployment, Oracle WebLogic Server, and JBoss Application Server.

If you use zRule Execution Server for z/OS, then rule sessions and XUs are prepackaged and their versions are aligned.

To prevent the loss of work, you must notify the users that you plan to upgrade the system progressively and all of their work must be committed before you start the upgrade. To complete a rolling upgrade, you must upgrade all of the runtime components and assets to Vn+1.

The following diagram shows the architecture of Operational Decision Manager Vn before you start a rolling upgrade:

Operational Decision Manager architecture in Vn

Sequence of rolling upgrade

You must upgrade the components in the following sequence:
  1. Decision Server Rules console
  2. Execution stacks
    1. zRule Execution Server for z/OS - for z/OS users only
    2. XUs and rule sessions
  3. zRule Execution Server for z/OS client libraries - for z/OS users only
  4. Decision Center
  5. Rule Designer
The following diagram shows the order of the components and assets to be upgraded:
Order of Operational Decision Manager components and assets to be upgraded in Vn+1
Parent topic: Rolling upgrade of Operational Decision Manager