The Rational ClearCase scheduler
The Rational® ClearCase® scheduler
provides a way to automate periodic maintenance on hosts that are configured
with support for local VOBs and views.
The scheduler’s work is defined in terms of jobs and tasks.
- A job is a data structure that defines the execution schedule for a task
and stores any exit status associated with the most recent execution of the
task. Each job runs a single task.
- A task is an executable program or script. A task may be run by more than
one job and, because a job can pass job-specific arguments to a task, the
operations performed by a task can be customized to suit the schedule on which
the job runs the task.
Unlike the general-purpose scheduled-execution utilities (
cron,
at,
...) associated with the operating systems on which
Rational ClearCase runs,
the scheduler is integrated with the
Rational ClearCase management
infrastructure and supports these functions:
- Centralized management with cleartool or the Rational ClearCase Administration
Console
- Access control based on user and group identity
- Flexible scheduling based on time of day, period, or execution of another
task
- A default set of tasks and jobs that run on every host
- Additional tasks and jobs that can be enabled when appropriate for a given
host
- Custom tasks and jobs
The scheduler is managed by the
albd_server. The
schedule program
is an interface to the job and task registries that provide the scheduler
with work to do. A small set of tasks and jobs run by default on all systems.
Others must be specifically enabled when appropriate. To modify jobs or tasks,
take one or more of the following steps:
- Modify the scheduler access control list (ACL), if necessary.
- Add jobs to the default daily and weekly local tasks
- Define new tasks and jobs for them to run.
- Managing the scheduler access control list
The schedule command uses a single access control
list (ACL) that determines who is allowed access to the scheduler’s task and
job registries and to the scheduler ACL itself.
- Creating a task
A set of standard tasks and a schedule for running them is installed
on every host that supports local VOBs and views. Although you cannot create,
change, or delete any standard tasks, you can define new tasks. You can also
customize two predefined tasks, one of which runs daily and the other weekly
in the default schedule, to add your own procedures to them and change their
schedules.
- Editing a task
You might need to edit an existing task definition
in the scheduler’s task registry. For example, if you move the task’s executable
program to another directory, you must change the pathname in the task definition
in the task registry.
- Deleting a custom task
Before you delete a task definition that you have created, you
must remove references to the task from all scheduled jobs. You cannot delete
any of the standard tasks.
- Managing jobs
You can create, delete, or edit jobs run by the scheduler. You
can also run a scheduled job immediately.
- Creating a job
You can create a job to run standard or custom tasks.
- Specifying a job’s schedule
A job can run under two kinds of schedules: sequential, which
runs the job immediately after another job finishes, or periodic, which runs
the job on specified days at specified times.
- Specifying job notifications
The scheduler can send e-mail notifications to recipients you specify.
You can also determine particular events that trigger notifications, such
as the start of a job or the end of a job that fails.
- Viewing job properties
Scheduled job properties include schedule information and execution
results.
- Editing job properties
- Running a job immediately
- Deleting a job