Release 1.6.0
A63730-01
Library |
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| Oracle
Enterprise Manager Concepts Guide
Release 1.6.0 A63730-01 |
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The Oracle Enterprise Manager provides a Job Scheduling system
and an Event Management system.
The Job Scheduling system provides stored and forwarding
capability which enables the automation of standard and repetitive tasks.
With the Job Scheduling system, you can create and manage jobs, schedule
execution of jobs, and view information about the jobs. Jobs can be scheduled
on a single node or multiple nodes in the network, and can be executed
immediately or scheduled in advance. If a site or its agent is down, the
job request is queued, and once the site can be contacted, the queued job
is submitted to the agent.
The Event Management system allows you to monitor the network
environment for specific events or conditions, such as loss of service
or lack of storage. In the Event Management window, you choose pre-defined
events or create custom events which the Intelligent Agents then detect
on specified sites in the network, if and when such events occur.
When an event is detected, the agent sends an alert to the
Console. You can also define the parameters for which you want to be notified,
including having specific system administrators notified when an event
occurs. Additionally, when registering an event set, you can create a fixit
job which would automatically correct the problem.
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The Job Scheduling system allows you to execute, schedule,
and manage tasks on remote sites. With the Job Scheduling system, you can
perform asynchronous tasks on multiple sites without having to maintain
connections to all those sites. In addition, jobs can run simultaneously
on different nodes in the system.
The Job Scheduling system, communication daemon, and Intelligent
Agents work in unison to schedule and execute jobs.
The following steps describe the process for scheduling and executing a job:
This section discusses the following benefits of the Job Scheduling system.
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In addition to creating your own custom jobs in the Job Scheduling
system, you can choose from a variety of pre-defined jobs which are installed
on Oracle Enterprise Manager. Such jobs include starting up or shutting
down databases or listeners and running SQL scripts or operating system
programs.
The Job Scheduling system is simple to use because the task
of scheduling and managing jobs is centralized in the Console. You only
need to submit a job once, regardless of the number of destinations on
which the job will run or the number of times it will run.
When you submit a job, the Console's communication daemon
sends the information about the job to the appropriate Intelligent Agents
on the destinations you selected. The agents are responsible for executing
the job on schedule and returning job status messages back to the daemon.
When a job is submitted to one or more destinations, it is
possible that any one of those sites may be down. If a site or its agent
is down, the communication daemon queues the job request that could not
be delivered to the site. Once the site can be contacted, the daemon submits
the queued job to the agent.
To schedule a job, you do not have to connect to the node
on which the job will be run. You only need to submit the job to the Console
and specify the destinations on which it should run. The destinations can
include nodes, databases, listeners, names servers, and user-defined groups
that have been created with the Map system.
The Job Scheduling system allows you to automate repetitive
and periodic tasks and the correction of problems. If a job has to be executed
repetitively or periodically, the agent(s) execute(s) the job automatically
without the need for DBA intervention. Messages about a job's status are
reported back to the Console.
For automating the correction of problems, the Job Scheduling
system works with the Event Management system. When you register an event
to be monitored by Oracle Enterprise Manager, you have the option of specifying
a fixit job, which will be executed to correct the problem if the event
occurs.
Jobs are implemented as Tool Command Language (Tcl) scripts.
Tcl is a scripting language that is used to write both job and event scripts.
Oracle has also extended Tcl (OraTcl) to include database-specific commands.
With OraTcl, you can do the following tasks:
Although you submit jobs from the Console, the job scripts
themselves reside on the Intelligent Agents. Because the manner in which
a job is implemented may depend on the platform, each agent keeps its own
set of job scripts.
Some DBA jobs involve more than one task. For example, before
making schema changes to a database, you may want to back up the database.
To accommodate these types of jobs, the Job Scheduling system allows you
to combine two or more jobs into one composite job. Each of the
jobs contained in the composite job is called a task.
Composite jobs can contain test conditions based on the success
of a task. For example, if a composite job consists of two tasks, starting
up a database and then running a SQL script, you can specify that the script
be run only if the database was successfully started.
The Job Scheduling system allows you to run jobs efficiently
on multiple remote nodes. When a job reaches a remote node, all the information
needed to run the job is transferred to the Intelligent Agent servicing
the node. When the job is executed, it is run by the agent on that node,
minimizing network traffic between the remote node and the Console and
daemon. The only communication between the agents and the Console and daemon
are the initial transmission of job information and any subsequent messages
about job status.
Because jobs are run independently by agents, you can submit
any number of jobs on multiple nodes without affecting the Console. For
example, you can submit several jobs and then immediately start another
task without waiting for the agents to schedule the jobs.
Because there is an agent residing on each managed node,
jobs can be run on multiple nodes simultaneously. For example, you can
submit a job to run a report on multiple databases worldwide. The job is
scheduled and run independently by each agent servicing each site. Therefore,
the jobs can be executed by their respective agents at the same time.
Jobs are normally run with your preferred credentials. Therefore,
you are only able to run jobs to perform functions that you can perform
logged into the machine directly.
Because jobs are categorized by service types, such as databases
or nodes, the Job Scheduling system knows which credentials to pass to
the agent. For instance, if the job runs on a node, the Job Scheduling
system passes either your preferred credentials for the node, or if none
are specified, the username and password you used when you logged into
the Console.
You can also choose to have a job run with the agent's credentials.
This flexibility allows a site to easily incorporate the Job Scheduling
system's authentication methods with existing security policies.
The Event Management system automates problem detection and
correction by having Intelligent Agents monitor for specified events throughout
the network and execute fixit jobs to correct the problems.
The following tasks can be done with the Event Management system:
The following steps describe the process of registering an event set:
When an event occurs, you can be notified in various ways,
such as electronic mail or paging. The Oracle Enterprise Manager Console
provides support for paging and e-mail when a pre-registered event is encountered.
The Console supports alphanumeric paging systems that use the TAP (Telocator
Alphanumeric Paging) protocol for automatic paging and both SMTP and MAPI
for email notification.
This section discusses the following features of the Event Management system:
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When an event set is registered, you have the option to specify
a fixit job, which is a job run by the agent if it detects the event. Events
and fixit jobs used together automate problem detection and correction.
This proactive management of an event ensures that a problem is corrected
before it noticeably impact end-users.
The Event Management system does not require that the Intelligent
Agents be the only mechanisms for error detection. Other tools and applications
can be integrated with the Event Management system and can detect events
independently of the Intelligent Agents. These tools and applications can
communicate directly with the Intelligent Agents.
For example, a third-party application can detect an event
on a node and report that event to the node's agent, which then sends the
message back to the Console as usual.
The Event Management system allows one person to monitor
a large system. If you are responsible for 100 databases, you cannot connect
to each database every day to check on its performance. However, the Event
Management system can effectively have the agents monitor all the databases
24 hours a day and can alert you if a problem is detected.
Monitoring a large number of sites with the Event Management
system puts minimal performance impact on the Console. Because the Intelligent
Agents perform the monitoring independent of the Console, many sites can
be monitored at once without slowing down other tasks.
In the Event Management system, event settings are stored
based on the administrator registering the event. Therefore, if you are
an administrator of a large system, you can customize your event systems
to your preferences and tasks, so that you receive only those messages
related to the events that you have submitted.
The Event Management system also allows you to focus on select
systems and events. Focus control is vital in a large system. If you do
not wish to monitor all sites or a large number of sites, you can pinpoint
only the sites you wish to monitor.
Oracle Enterprise Manager provides a variety of standard,
pre-defined event sets. Additional pre-defined events can be obtained with
the optional Oracle Diagnostics Pack which includes an application called
Oracle Advanced Events.
The standard, pre-defined event sets included with Oracle Enterprise Manager are fault management events:
Pre-defined Advanced Events that are included with the Oracle Diagnostics Pack include the following:
For more information on events, refer to the chapter on Events
Management in the Oracle Enterprise Manager Administrator's Guide,
or refer to the Oracle Enterprise Manager Console's online help for events.
As with jobs, events are OraTcl scripts that are stored on
the agent. Event scripts can save state information between executions
of an event script. This allows the agent to remember if it has detected
a certain event already and eliminates redundant event messages to the
Console. Saving state information also allows event scripts to maintain
a history of a database and adjust to behavior that is typical.
Note: Unlike job scripts, event scripts are
run with the permission of the agents.
The Intelligent Agent has been optimized to efficiently monitor
large numbers of systems in a node. Event tests are generally executed
by the agent process directly and can be run quickly.
