Introduction

This page describes the start-up message sequencing between a Primary and a Secondary UAG in a z/OS Sysplex; non-Sysplex UAGs are not affected.

The primary use of the start-up messaging is to control the number of Secondary agent licenses that are in use.

Overview

New licensing functionality provided by the 6.9.0.0 release simplifies and improves management of Universal Agents deployed within a z/OS Sysplex. The Universal Controller license contains a number of z/OS agents that are licensed to execute. A z/OS Universal Agent is granted permission to run as long the number of licensed z/OS agents is not exceeded. 

The Universal Agent identified as the primary agent (via the Universal Broker sysplex_role configuration option) is responsible for obtaining the remote license from Universal Controller and distributing it to the secondary agents running in the syplex. Only a primary agent may communicate with the Controller. Secondary agents can only communicate to the primary agent.

Primary/Secondary Agent Communication

When a Primary agent starts, it will initialize normally (Like a non-Sysplex UAG). Additionally, it will broadcast an (internal) XCF message to all members connected to the UAG Sysplex Group. (A group that encompasses all Primary and Secondary agents in the Sysplex that share the same system_id value.) When a Secondary agent receives this message, it will reply to it. Once the Primary agent receives a reply, it will send another XCF message to the replying Secondary agent containing its license information. The Secondary agent will use this information to decide to start processing, or shut down.

When a Secondary agent starts, it will initialize to the point where it can start to process. It will remain in a state where no tracking data of any kind will be processed. It will wait to be contacted by a Primary agent.

Note that tracking data will be collected by the various UAG exits and cached in the high common storage area while there is space. (The size of this area is defined by the high_common_storage configuration parameter.) Jobs will continue to run and UAGRERUN will function normally. However, job tracking, File Monitor and Syslog message information will not be processed until the Secondary receives a valid license.

If a Primary shuts down after granting licenses to Secondary agents, all Secondary agents will return to their initial state, waiting to be contacted by the Primary. Secondaries will have to re-acquire a license when the Primary restarts. If the number of licenses has been reduced for any reason (or the number of Secondaries increased), some Secondaries will not receive a new license and will have to stop processing.

Licenses are handed out by the Primary on a first come, first serve basis.

In case a Secondary agent starts after the Primary agent, the Primary agent will detect the startup and broadcast the same XCF message it broadcast on startup. Processing will then proceed as described above. (Agents can detect the startup, and shutdown, of any agent in their group through XCF events that are sent to all agents connected to the group.)