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Job and Event Systems

In a large, distributed database environment, the proportion of nodes per administrator increases rapidly, requiring tools that can automate tasks through "lights out" management and proactive event management. The Oracle Enterprise Manager provides a job scheduling system and an event management system.

The Job Scheduling System, which provides stored and forwarding capability, enables you to automate repetitive tasks and provides the kind of "lights out" management which is vital in a large, distributed environment.

Through the Event Management System, you can create and register event sets, modify or cancel registrations, view the status of services being monitored, view summary information about events that have occurred, and further manage event information.

To further automate problem detection and correction, you can specify for Oracle Enterprise Manager to perform tasks in response to an event. This ability of proactive management of an event allows you to ensure that a problem is corrected before it noticeably impact end-users.

The following topics are covered in this chapter:

Job Scheduling System

 The Job Scheduling System allows you to schedule and manage job tasks on remote sites. The process for scheduling a job is:

1.
From the Console Job system, you submit a job that you have set up.
2.
The communication daemon sends the job information to the appropriate intelligent agent(s).
3.
If a site or its agent is down, the communication daemon queues the job. Once the site can be contacted, the daemon will submit the queued job to the agent.
4.
The agent executes the job on schedule.
5.
The agent returns any related job messages back to the daemon for display in the Console.
The Job Scheduling System, communication daemon, and agents work in unison to schedule and execute the job. You can use the Job Scheduling System to 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 benefits of the job scheduling system are as follows

Predefined Job Tasks

 Enterprise Manager includes a variety of predefined jobs for you to select from. Some examples of predefined jobs are

You can also submit your own custom jobs to the Job Scheduling System.

Stored and Forwarding Job Scheduling

The Job Scheduling System is simple to use. Because the task of submitting and managing jobs is centralized in the Console, you only need to submit a job once, regardless of the number of nodes on which the job will run or how often it needs to be executed.

To schedule a job, you do not need to connect to the node on which the job will be run. Instead, you submit the job from the Console and specify the nodes or services on which it should run.

When you submit a job to a 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 job requests that could not be delivered to the site. Once the site can be contacted, the daemon will submit the queued job to the agent.

Lights Out Management

The Job Scheduling System allows you to automate repetitive and periodic tasks and problem correction. If the job has to be executed periodically, the agents reschedule the job without your intervention. Messages about a job's status are reported back to the Console.

The Job Scheduling System can be used with the Event Management System to automate problem correction. When you register an event to be monitored by Enterprise Manager, you have the option of specifying a fixit job, which will be executed to correct the problem if the event occurs.

Cross-Platform Job Scripts

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:

Although you submit a job from the Console, the job scripts themselves reside on the agent nodes. Because the manner in which a job is implemented may depend on the platform, each agent keeps its own set of job scripts.

This allows you to submit a job, such as backing up a database, without worrying about specifics of the platform. For example, you can select a group of databases residing on UNIX and VMS machines, and send one backup job request to back up the databases. The agents on those nodes run backup job scripts that are specific to their platforms.

Composite Jobs

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 predefined jobs into one composite job. Each of the predefined 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.

Scalability

The Job Scheduling System allows you to run jobs efficiently on multiple remote nodes. When you submit a job to run on a remote node, all the information needed to run the job is transferred to the 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 changes.

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.

In addition, because there is an intelligent 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 the agent that services each database. Therefore, the jobs can be executed by their respective agents at the same time.

Security and Jobs

Jobs are normally run with your preferred credentials; therefore, you will not be able to run jobs to perform functions that you could not perform if you were logged into the machine directly.

Because jobs are categorized by service types, such as database or node, the Job system knows which credentials to pass to the agent. 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. If the job runs on a service, such as a database, the Job Scheduling System also passes your preferred credentials to the service.

A job can also be 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.

Event Management System

The Event Management System allows you to monitor for specified events throughout the network, such as problems on a node or database, and optionally to execute a job to fix the problem. The Event system automates problem detection and correction.

The process to register an event set is:

1.
From the Console, you register a predefined event set or a set that you created.
2.
The communication daemon sends the event information to the appropriate intelligent agent(s).
3.
The agent does the monitoring and alerts you if the event occurs.
4.
Optionally, you can specify a fixit job to execute if the event occurs.
When an event occurs, you can be notified in various ways, such as electronic mail or paging. Also, events are always logged in the repository and can be viewed in the Console.

Features of the Event Management System are:

Proactive Events Management

 When an event set is registered, you have the option of specifying a fixit job for the event. A fixit job is a job that the agent runs if it detects the event. Events and fixit jobs used together allow you to automate problem detection and correction. This ability of proactive management of an event allows you to ensure that a problem is corrected before it noticeably impact end-users.

Unsolicited Error Detection

The Event Management System does not require that the intelligent agent be the only mechanism for error detection. The Event Management System can include other tools and applications that detect events independent of the intelligent agents. These tools and applications can be integrated into the Event Management System and 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 intelligent agent on that node. The agent then sends the message back to the Console as usual.

Scalability

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, using the Event Management System you can effectively monitor all the databases 24 hours a day, and be alerted if a problem is detected.

The Event system also allows you to focus on select systems and events. This control is vital in a large system. Rather than monitor all sites or a large number of sites, you can pinpoint only those services they wish to monitor.

On the other hand, an administrator can monitor a large number of sites with minimal performance impact on the Console. Because the intelligent agents perform the monitoring independent of the Console, an administrator has the option of monitoring many sites without slowing other tasks.

Pre-defined Event Sets

Standard pre-defined event sets are provided with Enterprise Manager. Advanced event sets are included with the optional Performance Pack.

The standard pre-defined events are the fault management events:

Some of pre-defined event sets that are included with the Performance Pack are:

Refer to the Oracle Enterprise Manager Performance Monitoring User's Guide.

Event Scripts

As with jobs, events are OraTcl scripts that are stored on the agent node. Event scripts can save state information. Saving a state between executions of an event script allows the agent to remember if it has detected a certain event already and eliminates redundant event messages to the Console. It 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 permissions of the agent.

Optimized Intelligent Agents

The intelligent agent has been optimized to monitor large numbers of systems and events efficiently. Event tests are generally executed by the agent process directly and can be run quickly.


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