Context

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•   Service Execution
  •   Assign and Control Delivery Resources

Details

The IBM® Tivoli® Workload Scheduler management of delivery resources is based on a database that contains the definitions of the scheduling objects. There are two versions of scheduling objects in the database depending on the placement of the main workload controller; it can be based on a mainframe computer (in this case, z/OS) or based on a distributed platform.

IBM Tivoli Workload Scheduler gives to operators and administrators the ability to manage the physical and logical entities that are involved in the execution of a scheduling plan.

To establish a new computer as one of the delivery resources of Tivoli Workload Scheduler, the administrator must install the product on the system and must configure it to accept a workload plan from Tivoli Workload Scheduler master domain manager (MDM) (or from one Tivoli Workload Scheduler domain manager), or to designate the computer itself as the MDM (the controller, in the case of z/OS). The installation procedure can be performed in various ways. On the distributed platforms, the selections are with user interaction from a GUI, from a command line, or unattended (controlled by other tools like IBM Tivoli Configuration Manager).

The installation procedures on the distributed environments are described in the book IBM Tivoli Workload Scheduler - Planning and Installation Guide Version 8.3 , those required for a z/OS installation are contained in the book IBM Tivoli Workload Scheduler for z/OS - Installation Guide Version 8.2 .

To perform any workload, the new established Tivoli Workload Scheduler workstation needs to have an execution plan, either self-generated (MDM or Controller) or received from the MDM/DM. The new Tivoli Workload Scheduler workstation is passive in receiving the plan, for example, the plan will need to be pushed from the MDM. MDM needs to know about this new workstation by using the definitions that are found in the scheduling objects database. A new workstation can be defined active (default) or inactive (planned for future use or being decommissioned). When inactive, the workstation will not receive any new execution plan delivery.

The Tivoli Workload Scheduler workstation has a set of attributes that allows limiting the number of Tivoli Workload Scheduler scheduled jobs that can be active at the same time (the so called CPU limit) or to prevent low priority jobs from entering into execution (CPU fence). Operators can modify these values to control the conditions of workflow execution and change the resources utilization during workload processing.

Additionally Tivoli Workload Scheduler workstations can be stopped and re-started by an operator. This capability means that a single resource can stop its processing of the workflow.

When the FTA workstation connection link with its Tivoli Workload Scheduler Domain Manager is down or unavailable, workflow can keep going on the workstation as long as it doesn’t require results from another resource, for which the MDM or the DM is acting as a broker. Operators can monitor link status of the workstation and perform actions to reestablish the link.

The jobs that execute a task on a workstation require that the corresponding service or task is available on the workstation, but the management of them is not under the scope of Tivoli Workload Scheduler.

With appropriate definitions of workstations, it is possible to establish a workstation as a backup workstation for the Master Domain Manager or of a Domain Manager, and it is possible to use Tivoli Workload Scheduler to switch the role of the MDM/DM over to the defined backup workstation, allowing appropriate control of the workload from an alternate workstation if the original MDM/DM is suffering from unavailability conditions.

Additional delivery resources that might be involved during a plan execution are the Tivoli Workload Scheduler resources (also known as Global Resources and Special Resources in z/OS terms). These are logical entities that are defined on the scheduling objects database that represent physical or logical resources that are required during job processing. Examples of Tivoli Workload Scheduler resources might be a tape driver required for a backup job, a database for a query job, or a CICS subsystem for a transactional job.

Tivoli Workload Scheduler resources are either unavailable or available with specific quantities. Tivoli Workload Scheduler will not schedule a resource that is depending on a job if it requires a resource that is not available or is available but has insufficient quantity.

Tivoli Workload Scheduler offers manage the status and availability of Tivoli Workload Scheduler resources through specialized commands that can be issued either manually from an operator when a physical or logical resource is actually made available or is in an automatic fashion with activation triggered by events that are generated by applications that sense availability of the physical resources.

One special case of a Tivoli Workload Scheduler resource is the file (or the dataset on z/OS) that offers native OS management of availability.

The full details about Tivoli Workload Scheduler resources can be found on the following books.
For z/OS, see Chapter 5 of IBM Tivoli Workload Scheduler for z/OS - Managing the Workload Version 8.2 . For distributed systems, see IBM Tivoli Workload Scheduler Reference Guide Version 8.3 , Chapter 3 under the keyword "needs", Chapter 5 under the command "resource," and Chapter 6 under title "release".

Chapters 19 and 25 of the book IBM Tivoli Workload Scheduler Job Scheduling Console User's Guide Version 8.3 describe how to perform the same activities as described above to manage Tivoli Workload Scheduler resources from the JSC interface.

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