Tivoli Workload Scheduler end-to-end scheduling architecture

Scheduling is the nucleus of the data center. Orderly, reliable sequencing and management of process execution is an essential part of IT management. Workloads are increasing, accelerated by electronic commerce. Making things more complex is the dependencies between jobs in different environments. For example, a customer can fill out an order form on their Web browser that will trigger a UNIX job that acknowledges the order, an AS/400 job that orders parts, an z/OS job hat debits the customer’s bank account, and a Windows NT job that prints a document and address labels. Each job must run only after the job before it has completed. The Tivoli Workload Scheduler 8.1 suite provides an integrated solution for running this kind of complicated workload. The Tivoli Workload Scheduler (TWS) 8.1 suite includes Tivoli Workload Scheduler and Tivoli Workload Scheduler for z/OS, as well as the Job Scheduling Console. Tivoli Workload Scheduler and Tivoli Workload Scheduler for z/OS can combined together to make end-to-end scheduling work, where both mainframe and distributed workloads are controlled from a Tivoli Workload Scheduler for z/OS engine. In this document we will investigate the end-to-end scheduling architecture and its components.

End-to-end scheduling is based on the ability to directly connect a Tivoli Workload Scheduler domain manager, and its underlying agents and domains, to the Tivoli Workload Scheduler for z/OS engine. The engine is seen by the distributed network as the master domain manager. Tivoli Workload Scheduler for z/OS also creates the plan for the distributed network and sends it to the domain manager. The domain manager sends a copy of the plan to each of its linked agents and subordinate domain managers for execution.

The Tivoli Workload Scheduler domain manager acts as the broker for the distributed network by resolving all dependencies for the subordinate managers and agents. It sends its updates (in the form of events) to Tivoli Workload Scheduler for z/OS so that it can update the plan accordingly. Tivoli Workload Scheduler for z/OS handles its own jobs and notifies the domain manager of all the status changes of the Tivoli Workload Scheduler for z/OS jobs that involve the Tivoli Workload Scheduler plan. In this configuration, the domain manager and all the distributed agents recognize Tivoli Workload Scheduler for z/OS as the master domain manager and notify it of all the changes occurring in their own plans. At the same time, the agents are not permitted to interfere with the Tivoli Workload Scheduler for z/OS jobs, since they are viewed as running on the master that is the only node that is in charge of them.

With this version of Tivoli Workload Scheduler for z/OS, the fault tolerant agents replace the Tivoli OPC tracker agents and make scheduling possible on the distributed platform with more reliable, fault tolerant, and scalable agents.

In the following figure (Figure-1) you can see a Tivoli Workload Scheduler network managed by a Tivoli Workload Scheduler for z/OS engine.

As you can see from the figure end-to-end scheduling is accomplished by connecting a Tivoli Workload Scheduler domain manager directly to the Tivoli Workload Scheduler for z/OS engine. The master domain manager is the Tivoli Workload Scheduler for z/OS engine.

Tivoli Workload Scheduler for z/OS also allows you to access job streams (schedules in Tivoli Workload Scheduler) and add them to the current plan in Tivoli Workload Scheduler for z/OS. In addition, you can build dependencies among Tivoli Workload Scheduler for z/OS job streams and Tivoli Workload Scheduler jobs. From Tivoli Workload Scheduler for z/OS, you can monitor and control the distributed agents.

In the Tivoli Workload Scheduler for z/OS current plan, you can specify jobs to run on workstations in the Tivoli Workload Scheduler network. The TWS for z/OS engine passes the job information to the Symphony file in the TWS for z/OS server, which in turn passes the Symphony file to the TWS domain manager (DMZ) to distribute and process. In turn, TWS reports the status of running and completed jobs back to the current plan for monitoring in the Tivoli Workload Scheduler for z/OS engine.

Tivoli Workload Scheduler for z/OS end-to-end components

To run the Tivoli Workload Scheduler for z/OS end-to-end you must have a Tivoli Workload Scheduler for z/OS server start task dedicated for end-to-end scheduling. It is also possible to use the same server to communicate with the Job Scheduling Console. The Tivoli Workload Scheduler for z/OS uses TCP/IP for communication.

The Tivoli Workload Scheduler for z/OS engine uses the end-to-end server to communicate events to the distributed agents. The end-to-end server will start multiple tasks and processes using the z/OS UNIX System Services (USS).

The Tivoli Workload Scheduler for z/OS end-to-end scheduling engine is comprised of three major components:

• The Tivoli Workload Scheduler for z/OS controller: Manages database objects, creates plans with the workload, and executes and monitors the workload in the plan.
• The Tivoli Workload Scheduler for z/OS server: Acts as the Tivoli Workload Scheduler master domain manager. It receives a part of the current plan from the Tivoli Workload Scheduler for z/OS engine, which contains job and job streams to be executed in the Tivoli Workload Scheduler network. The server is the focal point for all communication to and from the Tivoli Workload Scheduler network.
• The Tivoli Workload Scheduler primary domain manager: Serves as the communication hub between the Tivoli Workload Scheduler for z/OS server and the distributed Tivoli Workload Scheduler network. The domain manager is connected directly to the Tivoli Workload Scheduler for z/OS master domain manager in USS.