Feedback
Table Of Contents
Embedded Event Manager Overview
Information About Embedded Event Manager
Embedded Event Manager 2.1 (Software Modularity)
Embedded Event Manager Actions
Embedded Event Manager Environment Variables
Embedded Event Manager Policy Creation
Feature Information for Embedded Event Manager Overview
Embedded Event Manager Overview
First Published: October 31, 2005Last Updated: October 9, 2007Embedded Event Manager (EEM) is a distributed and customized approach to event detection and recovery offered directly in a Cisco IOS device. EEM offers the ability to monitor events and take informational, corrective, or any desired action when the monitored events occur or when a threshold is reached. An EEM policy is an entity that defines an event and the actions to be taken when that event occurs.
This module contains a technical overview of EEM. EEM can be used alone, or with other network management technologies, to help monitor and maintain your network. Before you begin to implement EEM, it is important that you understand the information presented in this module.
Finding Feature Information in This Module
Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Embedded Event Manager Overview" section.
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
•
Information About Embedded Event Manager
•
Information About Embedded Event Manager
To use EEM in your network, you should understand the following concepts:
•
•
•
•
Embedded Event Manager
Event tracking and management has traditionally been performed by devices external to the networking device. Embedded Event Manager (EEM) has been designed to offer event management capability directly in Cisco IOS devices. The on-device, proactive event management capabilities of EEM are useful because not all event management can be done off router because some problems compromise communication between the router and the external network management device. Capturing the state of the router during such situations can be invaluable in taking immediate recovery actions and gathering information to perform root-cause analysis. Network availability is also improved if automatic recovery actions are performed without the need to fully reboot the routing device.
EEM is a flexible, policy-driven framework that supports in-box monitoring of different components of the system with the help of software agents known as event detectors. Figure 1 shows the relationship between the EEM server, core event publishers (event detectors), and the event subscribers (policies). Basically, event publishers screen events and publish them when there is a match on an event specification that is provided by the event subscriber. Event detectors notify the EEM server when an event of interest occurs. The EEM policies that are configured using the Cisco IOS command-line interface (CLI) then implement recovery on the basis of the current state of the system and the actions specified in the policy for the given event.
EEM offers the ability to monitor events and take informational or corrective action when the monitored events occur or when a threshold is reached. An EEM policy is an entity that defines an event and the actions to be taken when that event occurs. There are two types of EEM policies: an applet or a script. An applet is a simple form of policy that is defined within the CLI configuration. A script is a form of policy that is written in Tool Command Language (Tcl).
Figure 1 Embedded Event Manager Core Event Detectors
Embedded Event Manager 1.0
EEM 1.0 is supported in Cisco IOS Releases 12.0(26)S and 12.3(4)T and later releases and introduced Embedded Event Manager. EEM 1.0 introduced the following event detectors:
•
•
EEM 1.0 introduced the following actions:
•
•
•
•
Embedded Event Manager 2.0
EEM 2.0 is supported in Cisco IOS Release 12.2(25)S and later releases and introduced some new features. EEM 2.0 introduced the following event detectors:
•
•
•
•
•
EEM 2.0 introduced the following actions:
•
•
•
The ability to run a Cisco defined sample policy written using Tool Command Language (Tcl) was introduced. A sample policy was provided that could be stored in the system policy directory.
Embedded Event Manager 2.1
EEM 2.1 is supported in Cisco IOS Release 12.3(14)T, 12.2(18)SXF5, 12.2(28)SB, 12.2(33)SRA, and later releases, and introduced some new features. EEM 2.1 introduced the following new event detectors:
•
•
•
EEM 2.1 introduced the following actions:
•
•
•
•
EEM 2.1 also permits multiple concurrent policies to be run using the new event manager scheduler script command. Support for Simple Network Management Protocol (SNMP) event detector rate-based events is provided as is the ability to create policies using Tool Command Language (Tcl).
Embedded Event Manager 2.1 (Software Modularity)
EEM 2.1 (Software Modularity) is supported in Cisco IOS Release 12.2(18)SXF4 and later releases on Cisco IOS Software Modularity images. EEM 2.1 (Software Modularity) introduced the following event detectors:
•
•
•
EEM 2.1 for Software Modularity introduced the ability to display EEM reliability metric data for processes.
Note
Embedded Event Manager 2.2
EEM 2.2 is supported in Cisco IOS Release 12.4(2)T, 12.2(31)SB3, 12.2(33)SRB, and later releases, and introduced some new features. EEM 2.2 introduced the following event detectors:
•
•
•
EEM 2.2 introduced the following actions:
•
•
Embedded Event Manager 2.3
EEM 2.3 is supported in Cisco IOS Release 12.2(33)SXH and later releases for the Cisco Catalyst 6500 Series switches and introduces enhancements to the Generic Online Diagnostics (GOLD) Event Detector on that product.
•
•
–
–
–
–
•
–
–
–
–
–
These enhancements result in reduced mean time to recovery (MTTR) and higher availability through improved automation and fault detection.
Event Detectors
Embedded Event Manager (EEM) uses software programs known as event detectors to determine when an EEM event occurs. Event detectors are separate systems that provide an interface between the agent being monitored, for example Simple Network Management Protocol (SNMP), and the EEM policies where an action can be implemented. Some event detectors are available on every Cisco IOS release, but most event detectors have been introduced in a specific release. For details of which event detector is supported in each Cisco IOS release, see the EEM Event Detectors Available by Cisco IOS Release concept in the "Writing Embedded Event Manager Policies Using the Cisco IOS CLI" or the "Writing Embedded Event Manager Policies Using Tcl" modules. EEM contains the following event detectors.
Application-Specific Event Detector
The application-specific event detector allows any Embedded Event Manager policy to publish an event. When an EEM policy publishes an event it must use an EEM subsystem number of 798 with any event type. If an existing policy is registered for subsystem 798 and a specified event type, a second policy of the same event type will trigger the first policy to run when the specified event is published.
CLI Event Detector
The CLI event detector screens command-line interface (CLI) commands for a regular expression match. When a match is found, an event is published. The match logic is performed on the fully expanded CLI command after the command is successfully parsed and before it is executed. The CLI event detector supports three publish modes:
•
•
•
Counter Event Detector
The counter event detector publishes an event when a named counter crosses a specified threshold. There are two or more participants that affect counter processing. The counter event detector can modify the counter, and one or more subscribers define the criteria that cause the event to be published. After a counter event has been published, the counter monitoring logic can be reset to start monitoring the counter immediately or it can be reset when a second threshold—called an exit value—is crossed.
Enhanced Object Tracking Event Detector
The enhanced object tracking (EOT) event detector publishes an event when the status of a tracked object changes. Object tracking was first introduced into the Hot Standby Router Protocol (HSRP) as a simple tracking mechanism that allowed you to track the interface line-protocol state only. If the line-protocol state of the interface went down, the HSRP priority of the router was reduced, allowing another HSRP router with a higher priority to become active.
Object tracking was enhanced to provide complete separation between the objects to be tracked and the action to be taken by a client when a tracked object changes. Thus, several clients such as HSRP, VRRP, or GLBP can register their interest with the tracking process, track the same object, and each take different action when the object changes. Each tracked object is identified by a unique number that is specified on the tracking command-line interface (CLI). Client processes use this number to track a specific object. The tracking process periodically polls the tracked objects and notes any change of value. The changes in the tracked object are communicated to interested client processes, either immediately or after a specified delay. The object values are reported as either up or down.
Enhanced object tracking is now integrated with EEM to allow EEM to report on a status change of a tracked object and to allow enhanced object tracking to track EEM objects. A new type of tracking object—a stub object—is created. The stub object can be manipulated using the existing CLI commands that already allow tracked objects to be manipulated.
GOLD Event Detector
The GOLD event detector publishes an event when a GOLD failure event is detected on a specified card and subcard.
Interface Counter Event Detector
The interface counter event detector publishes an event when a generic Cisco IOS interface counter for a specified interface crosses a defined threshold. A threshold can be specified as an absolute value or an incremental value. If the incremental value is set to 50, for example, an event would be published when the interface counter increases by 50.
After an interface counter event has been published, the interface counter monitoring logic is reset using two methods. The interface counter is reset either when a second threshold—called an exit value—is crossed or when an elapsed period of time occurs.
None Event Detector
The none event detector publishes an event when the Cisco IOS event manager run CLI command executes an EEM policy. EEM schedules and runs policies on the basis of an event specification that is contained within the policy itself. An EEM policy must be identified and registered to be permitted to run manually before the event manager run command will execute.
OIR Event Detector
The online insertion and removal (OIR) event detector publishes an event when one of the following hardware insertion or removal events occurs:
•
•
Route Processors (RPs), line cards, or feature cards can be monitored for OIR events.
Resource Event Detector
The resource event detector publishes an event when the Embedded Resource Manager (ERM) reports an event for the specified policy. The ERM infrastructure tracks resource depletion and resource dependencies across processes and within a system to handle various error conditions. The error conditions are handled by providing an equitable sharing of resources between various applications. The ERM framework provides a communication mechanism for resource entities and allows communication between these resource entities from numerous locations. The ERM framework also helps in debugging CPU and memory-related issues. The ERM monitors system resource usage to better understand scalability needs by allowing you to configure threshold values for resources such as the CPU, buffers, and memory. The ERM event detector is the preferred method for monitoring resources in Cisco IOS software but the ERM event detector is not supported in Software Modularity images. For more details about ERM, see the "Embedded Resource Manager" chapter in the "System Monitoring and Logging" part of the Cisco IOS Network Management Configuration Guide, Release 12.4T.
RF Event Detector
The redundancy framework (RF) event detector publishes an event when one or more RF events occur during synchronization in a dual Route Processor (RP) system. The RF event detector can also detect an event when a dual RP system continuously switches from one RP to another RP (referred to as a ping-pong situation).
SNMP Event Detector
The SNMP event detector allows a standard SNMP MIB object to be monitored and an event to be generated when the object matches specified values or crosses specified thresholds.
Syslog Event Detector
The syslog event detector allows for screening syslog messages for a regular expression pattern match. The selected messages can be further qualified, requiring that a specific number of occurrences be logged within a specified time. A match on a specified event criteria triggers a configured policy action.
System Manager Event Detector
The system manager event detector generates events for Cisco IOS Software Modularity process start, normal or abnormal stop, and restart events. The events generated by the system manager allows policies to change the default behavior of the process restart.
Timer Event Detector
The timer event detector publishes events for the following four different types of timers:
•
•
•
•
Watchdog System Monitor (IOSWDSysMon) Event Detector for Cisco IOS
The Cisco IOS watchdog system monitor event detector publishes an event when one of the following occurs:
•
•
Note
Two events may be monitored at the same time, and the event publishing criteria can be specified to require one event or both events to cross their specified thresholds.
Watchdog System Monitor (WDSysMon) Event Detector for Cisco IOS Software Modularity
The Cisco IOS Software Modularity watchdog system monitor event detector detects infinite loops, deadlocks, and memory leaks in Cisco IOS Software Modularity processes.
Embedded Event Manager Actions
The CLI-based corrective actions that are taken when event detectors report events enable a powerful on-device event management mechanism. Some EEM actions are available on every Cisco IOS release, but most EEM actions have been introduced in a specific release. For details of which EEM action is supported in each Cisco IOS release, see the EEM Actions Available by Cisco IOS Release concept in the "Writing Embedded Event Manager Policies Using the Cisco IOS CLI" or the "Writing Embedded Event Manager Policies Using Tcl" modules. EEM supports the following actions:
•
•
•
•
•
•
•
•
•
•
•
•
•
EEM action CLI commands contain an EEM action label that is a unique identifier that can be any string value. Actions are sorted and run in ascending alphanumeric (lexicographical) key sequence using the label as the sort key. If you are using numbers as labels be aware that alphanumerical sorting will sort 10.0 after 1.0, but before 2.0, and in this situation we recommend that you use numbers such as 01.0, 02.0, and so on, or use an initial letter followed by numbers.
Embedded Event Manager Environment Variables
EEM allows environment variables to be used in EEM policies. Tool Command Language (Tcl) allows global variables to be defined that are known to all procedures within a Tcl script. EEM allows environment variables to be defined using a CLI command, the event manager environment command, for use within an EEM policy. All EEM environment variables are automatically assigned to Tcl global variables before a Tcl script is run. There are three different types of environment variables associated with Embedded Event Manager:
•
•
•
Cisco-defined environment variables (see Table 1) and Cisco system-defined environment variables may apply to one specific event detector or to all event detectors. Environment variables that are user-defined or defined by Cisco in a sample policy are set using the event manager environment command. Variables that are used in the EEM policy must be defined before you register the policy. A Tcl policy contains a section called "Environment Must Define" that can be defined to check that any required environment variables are defined before the policy runs.
Cisco built-in environment variables are a subset of the Cisco-defined environment variables and the built-in variables are available to EEM applets only. The built-in variables can be read-only or can be read and write, and these variables may apply to one specific event detector or to all event detectors. For more details and a table listing the Cisco system-defined variables, see the "Writing Embedded Event Manager Policies Using the Cisco IOS CLI" module.
Note
Table 1 describes the Cisco-defined variables used in the sample EEM policies. Some of the environment variables do not have to be specified for the corresponding sample policy to run and these are marked as optional.
Table 1 Cisco-Defined Environmental Variables and Examples
_config_cmd1
The first configuration command that is executed.
interface Ethernet1/0
_config_cmd2
(Optional) The second configuration command that is executed.
no shutdown
_crash_reporter_debug
(Optional) A value that identifies whether debug information for tm_crash_reporter.tcl will be enabled.
1
_crash_reporter_url
The URL location to which the crash report is sent.
http://www.yourdomain.com/
fm/interface_tm.cgi_cron_entry
A CRON specification that determines when the policy will run. See the "Writing Embedded Event Manager Policies Using Tcl" module for more information about how to specify a cron entry.
0-59/1 0-23/1 * * 0-7
_email_server
A Simple Mail Transfer Protocol (SMTP) mail server used to send e-mail.
mailserver.yourdomain.com
_email_to
The address to which e-mail is sent.
engineer@yourdomain.com
_email_from
The address from which e-mail is sent.
devtest@yourdomain.com
_email_cc
The address to which the e-mail is be copied.
manager@yourdomain.com
_show_cmd
The CLI show command to be executed when the policy is run.
show version
_syslog_pattern
A regular expression pattern match string that is used to compare syslog messages to determine when the policy runs.
.*UPDOWN.*FastEthernet
0/0.*_tm_fsys_usage_cron
(Optional) A CRON specification that is used in the event_register keyword extension. If unspecified, the _tm_fsys_usage.tcl policy is triggered once per minute.
0-59/1 0-23/1 * * 0-7
_tm_fsys_usage_debug
(Optional) When this variable is set to a value of 1, disk usage information is displayed for all entries in the system.
1
_tm_fsys_usage_
freebytes(Optional) Free byte threshold for systems or specific prefixes. If free space falls below a given value, a warning is displayed.
disk2:98000000
_tm_fsys_usage_percent
(Optional) Disk usage percentage thresholds for systems or specific prefixes. If disk usage percentage exceeds a given percentage, a warning is displayed. If unspecified, the default disk usage percentage is 80 percent for all systems.
nvram:25 disk2:5
Embedded Event Manager Policy Creation
EEM is a policy driven process in which the EEM policy engine receives notifications when faults and other events occur in the Cisco IOS software system. Embedded Event Manager policies implement recovery based on the current state of the system and the actions specified in the policy for a given event. Recovery actions are triggered when the policy is run.
Although there are some EEM CLI configuration and show commands, EEM is implemented through the creation of policies. An EEM policy is an entity that defines an event and the actions to be taken when that event occurs. There are two types of EEM policies: an applet or a script. An applet is a simple form of policy that is defined within the CLI configuration. A script is a form of policy that is written in Tcl.
The creation of an EEM policy involves:
•
•
•
•
There are two ways to create an EEM policy. The first method is to write applets using CLI commands, and the second method is to write Tcl scripts. Cisco provides enhancements to Tcl in the form of Tcl command extensions that facilitate the development of EEM policies. Scripts are defined off the networking device using an ASCII editor. The script is then copied to the networking device and registered with EEM. When a policy is registered with the Embedded Event Manager, the software examines the policy and registers it to be run when the specified event occurs. Policies can be unregistered or suspended. Both types of policies can be used to implement EEM in your network.
For details on writing EEM policies using the Cisco IOS CLI, see the "Writing Embedded Event Manager Policies Using the Cisco IOS CLI" module.
For details on writing EEM policies using Tcl, see the "Writing Embedded Event Manager Policies Using Tcl" module.
Where to Go Next
•
•
•
Additional References
The following sections provide references related to EEM.
Related Documents
Software Modularity commands (including EEM commands): complete command syntax, defaults, command mode, command history, usage guidelines, and examples
Cisco IOS Software Modularity Command Reference, Release 12.2(18)SXF4
Network Management commands (including EEM commands): complete command syntax, defaults, command mode, command history, usage guidelines, and examples
•
•
•
Embedded Event Manager policy writing using the CLI
"Writing Embedded Event Manager Policies Using the Cisco IOS CLI" module
Embedded Event Manager policy writing using Tcl
Configuration of other network management technologies
Cisco IOS Network Management Configuration Guide, Release 12.4T.
Standards
No new or modified standards are supported, and support for existing standards has not been modified.
—
MIBs
CISCO-EMBEDDED-EVENT-MGR-MIB
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
No new or modified RFCs are supported, and support for existing RFCs has not been modified.
—
Technical Assistance
Feature Information for Embedded Event Manager Overview
Table 2 lists the features in this module and provides links to specific configuration information. Only features that were introduced or modified in Cisco IOS Releases 12.3(14)T, 12.2(25)S, 12.0(26)S, 12.2(18)SXF4, 12.2(28)SB, 12.2(33)SRA, or a later release appear in the table.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note
Table 2 Feature Information for Embedded Event Manager Overview
Embedded Event Manager 1.0
12.0(26)S
12.3(4)TEEM 1.0 introduced Embedded Event Manager applet creation with the SNMP and Syslog event detectors. EEM 1.0 also introduced the following actions: generating prioritized syslog messages, generating a CNS event for upstream processing by Cisco CNS devices, reloading the Cisco IOS software, and switching to a secondary processor in a fully redundant hardware configuration.
The following sections provide information about this feature:
•
•
The following commands were introduced by this feature: action cns-event, action force-switchover, action reload, action syslog, debug event manager, event manager applet, event snmp, event syslog, show event manager policy registered.
Embedded Event Manager 2.0
12.2(25)S
EEM 2.0 introduced the application-specific event detector, the counter event detector, the interface counter event detector, the timer event detector, and the IOSWDSysMon event detector. New actions include setting and modifying a named counter, publishing an application-specific event, and generating an SNMP trap. The ability to define environment variables and to run a sample EEM policy (included in the software) written using Tcl was introduced.
The following sections provide information about this feature:
•
•
•
The following commands were introduced by this feature: action counter, action publish-event, action snmp-trap, event application, event counter, event interface, event ioswdsysmon, event manager environment, event manager history size, event manager policy, event manager scheduler suspend, event timer, show event manager environment, show event manager history events, show event manager history traps, show event manager policy available, show event manager policy pending.
Embedded Event Manager 2.1
12.3(14)T 12.2(18)SXF5
12.2(28)SB
12.2(33)SRAEEM 2.1 introduced some new event detectors and actions with new functionality to allow EEM policies to be run manually and the ability to run multiple concurrent policies. Support for Simple Network Management Protocol (SNMP) event detector rate-based events was provided as was the ability to create policies using Tool Command Language (Tcl).
The following sections provide information about this feature:
•
•
•
The following commands were introduced or modified by this feature: action cli, action counter, action info, action mail, action policy, debug event manager, event cli, event manager directory user, event manager policy, event manager run, event manager scheduler script, event manager session cli username, event none, event oir, event snmp, event syslog, set (EEM), show event manager directory user, show event manager policy registered, show event manager session cli username.
Embedded Event Manager 2.1 (Software Modularity)
12.2(18)SXF4
Cisco IOS Software Modularity imagesEEM 2.1 for Software Modularity images introduced the GOLD, system manager, and WDSysMon (Cisco IOS Software Modularity watchdog) event detectors, and the ability to display Cisco IOS Software Modularity processes and process metrics.
The following sections provide information about this, feature:
•
•
•
•
The following commands were introduced by this feature: event gold, event process, show event manager metric process.
Note
Embedded Event Manager 2.2
12.4(2)T
12.2(31)SB3
12.2(33)SRBEEM 2.2 introduced the enhanced object tracking, resource, and RF event detectors. The actions of reading and setting the state of a tracked object were also introduced.
The following sections provide information about this feature:
•
•
•
The following commands were introduced or modified by this feature: action track read, action track set, default-state, event resource, event rf, event track, show track, track stub-object.
Embedded Event Manager 2.3
12.2(33)SXH
The event gold command was modified and the action-notify, testing-type, test-name, test-id, consecutive-failure, platform-action, and the maxrun keywords were added.
Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.© 2005-2007 Cisco Systems, Inc. All rights reserved.
