Snmpman Web Logic SNMP Management Guide

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BEAWebLogic
Server®
WebLogic SNMP
Management Guide
Version 9.0 BETA
Revised: December 15, 2004
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Copyright
Copyright © 2004 BEA Systems, Inc. All Rights Reserved.
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WebLogic SNMP Management Guide v
Contents
About This Document
Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
e-docs Web Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
How to Print the Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Contact Us! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Documentation Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
1. Introduction to the WebLogic SNMP Agent
The SNMP Agent/Manager Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
The Role of the SNMP Agent in a WebLogic Server Domain . . . . . . . . . . . . . . . . . . . . . 1-2
WebLogic Server Managed Resources and MBeans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
SNMP MIB for WebLogic Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Browsing the MIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Object Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
OIDs for Types and Instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
SNMP Community Names. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Using Community Names to Specify Target Servers in Management Requests . . . . 1-6
2. WebLogic Trap Notifications
Format of WebLogic Trap Notifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Automatically Generated WebLogic SNMP Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Log Message Traps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Variable Bindings in Log Message Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
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Monitor Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Variable Bindings in Monitor Traps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Attribute Change Traps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Variable Bindings in Attribute Change Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
3. SNMP Proxies
SNMP Agent as Proxy for Other Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
The Microsoft Windows SNMP Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
A. Sources of SNMP Information
Reference Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Standards and Drafts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Obtaining RFCs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
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WebLogic SNMP Management Guide vii
About This Document
This document explains the management subsystem provided for configuring and monitoring
your WebLogic Server implementation. It covers the following topics:
zChapter 1, “Introduction to the WebLogic SNMP Agent,” describes basic concepts of
Simple Network Management Protocol as they apply to managing WebLogic Servers.
zChapter 2, “WebLogic Trap Notifications,” describes the characteristics of WebLogic
enterprise-specific SNMP trap notifications.
zChapter 3, “SNMP Proxies,” describes how WebLogic Server can function as a master
agent that proxies for other SNMP agents.
Audience
This document is intended mainly for system administrators who will be managing the WebLogic
Server application platform and its various subsystems.
e-docs Web Site
BEA product documentation is available on the BEA corporate Web site. From the BEA Home
page, click on Product Documentation.
How to Print the Document
You can print a copy of this document from a Web browser, one main topic at a time, by using
the File→Print option on your Web browser.
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About This Document
viii WebLogic SNMP Management Guide
A PDF version of this document is available on the WebLogic Server documentation Home page
on the e-docs Web site (and also on the documentation CD). You can open the PDF in Adobe
Acrobat Reader and print the entire document (or a portion of it) in book format. To access the
PDFs, open the WebLogic Server documentation Home page, click Download Documentation,
and select the document you want to print.
Adobe Acrobat Reader is available at no charge from the Adobe Web site at
http://www.adobe.com.
Contact Us!
Your feedback on BEA documentation is important to us. Send us e-mail at
docsupport@bea.com if you have questions or comments. Your comments will be reviewed
directly by the BEA professionals who create and update the documentation.
In your e-mail message, please indicate the software name and version you are using, as well as
the title and document date of your documentation. If you have any questions about this version
of BEA WebLogic Server, or if you have problems installing and running BEA WebLogic
Server, contact BEA Customer Support through BEA WebSupport at http://www.bea.com. You
can also contact Customer Support by using the contact information provided on the Customer
Support Card, which is included in the product package.
When contacting Customer Support, be prepared to provide the following information:
zYour name, e-mail address, phone number, and fax number
zYour company name and company address
zYour machine type and authorization codes
zThe name and version of the product you are using
zA description of the problem and the content of pertinent error messages
Documentation Conventions
The following documentation conventions are used throughout this document.
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WebLogic SNMP Management Guide ix
Convention Usage
Ctrl+Tab Keys you press simultaneously.
italics Emphasis and book titles.
monospace
text
Code samples, commands and their options, Java classes, data types,
directories, and file names and their extensions. Monospace text also
indicates text that the user is told to enter from the keyboard.
Examples:
import java.util.Enumeration;
chmod u+w *
config/examples/applications
.java
config.xml
float
monospace
italic
text
Placeholders.
Example:
String CustomerName;
UPPERCASE
MONOSPACE
TEXT
Device names, environment variables, and logical operators.
Examples:
LPT1
BEA_HOME
OR
{ } A set of choices in a syntax line.
[ ] Optional items in a syntax line. Example:
java utils.MulticastTest -n name -a address
[-p portnumber] [-t timeout] [-s send]
|Separates mutually exclusive choices in a syntax line. Example:
java weblogic.deploy [list|deploy|undeploy|update]
password {application} {source}
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About This Document
xWebLogic SNMP Management Guide
... Indicates one of the following in a command line:
• An argument can be repeated several times in the command line.
• The statement omits additional optional arguments.
• You can enter additional parameters, values, or other information
.
.
.
Indicates the omission of items from a code example or from a syntax line.
Convention Usage
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WebLogic SNMP Management Guide 1-1
CHAPTER 1
Introduction to the WebLogic SNMP
Agent
WebLogic Server® can use Simple Network Management Protocol (SNMP) to communicate
with enterprise-wide management systems. The WebLogic Server subsystem that gathers
WebLogic management data, converts it to SNMP communication modules (trap notifications),
and forwards the trap notifications to third-party SNMP management systems is called the
WebLogic SNMP agent. The WebLogic SNMP agent supports the SNMPv1 and SNMPv2
protocols.
Typically, you use SNMP to provide a single location from which to manage a heterogeneous
software and hardware environment.
The following sections describe the SNMP management model and how WebLogic Server
implements this model:
z“The SNMP Agent/Manager Model” on page 1-2
z“The Role of the SNMP Agent in a WebLogic Server Domain” on page 1-2
z“WebLogic Server Managed Resources and MBeans” on page 1-4
z“SNMP MIB for WebLogic Server” on page 1-4
z“SNMP Community Names” on page 1-6
For more information, refer to the following:
z“WebLogic SNMP Agent Command-Line Reference” in the WebLogic Server Command
Reference
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Introduction to the WebLogic SNMP Agent
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The SNMP Agent/Manager Model
SNMP management is based on the agent/manager model described in the network management
standards defined by the International Organization for Standardization (ISO). In this model, a
network/systems manager exchanges monitoring and control information about system and
network resources with distributed software processes called agents.
Any system or network resource that is manageable through the exchange of information is a
managed resource. This could be a software resource, such as a Java Database Connectivity
(JDBC) connection pool, or a hardware resource, such as a router.
Agents function as “collection devices” that gather and send data about the managed resource in
response to a request from a manager. In addition, agents often have the ability to issue
unsolicited reports to managers when they detect certain predefined thresholds or conditions on
a managed resource. In SNMP terminology, these unsolicited event reports are called trap
notifications.
A manager relies upon a database of definitions and information about the properties of managed
resources and the services the agents support — this makes up the Management Information Base
(MIB). When new agents are added to extend the management reach of a manager, the manager
must be provided with a new MIB component that defines the manageable features of the
resources managed through that agent. The manageable attributes of resources, as defined in an
SNMP-compliant MIB, are called managed objects. Defining the heterogeneous components of
an enterprise’s distributed systems within a common MIB on the management station provides a
unified perspective and single access point for managing system and network resources.
The Role of the SNMP Agent in a WebLogic Server Domain
The WebLogic SNMP agent runs on a domain’s Administration Server. (See Figure 1-1.)
A WebLogic Server administration domain is a logically related group of WebLogic Server
resources. Domains include a special WebLogic Server instance called the Administration
Server, which is the central point from which you configure and manage all resources in the
domain. Typically, you configure a domain to include additional WebLogic Server instances
called Managed Servers. You deploy applications, EJBs, and other resources on the Managed
Servers and use the Administration Server for configuration and management purposes only.
Using multiple Managed Servers lets you balance loads and provide failover protection for
critical applications, while using a single Administration Server simplifies the management of the
Managed Server instances. For more information about domains, refer to "Overview of
WebLogic Server Domains" in Configuring and Managing WebLogic Server.
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The Role of the SNMP Agent in a WebLogic Server Domain
WebLogic SNMP Management Guide 1-3
Figure 1-1 SNMP Management of a WebLogic Domain
You can use the WebLogic SNMP agent to do the following:
zRespond to simple GET requests from an SNMP manager for the current value of
WebLogic attributes.
zSend trap notifications to SNMP managers when the Administration Server starts and when
any Managed Server starts or shuts down.
zSend trap notifications to SNMP managers when messages are logged in a Managed Server
that satisfy criteria that you specify.
zSend trap notifications to SNMP managers when a WebLogic configuration attribute that
you specify has changed value.
zOffload polling of WebLogic attributes to the WebLogic Administration Server using
standard JMX monitors, based on thresholds and polling intervals that you define. A trap
notification is sent to the SNMP manager when the criteria you specify are satisfied.
Administration Server
SNMP Service (SNMP Agent)
Administration Server Host
Non-WebLogic
SNMP
Agent
SNMP
Management
Station
Request
Response
Proxy
Request Response
Traps Cache
GET
Managed
Server
Managed
Server
GET
GET
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zAct as a proxy agent that passes requests from an SNMP manager to other SNMP agents
(such as an Oracle database agent) on the same machine.
WebLogic Server Managed Resources and MBeans
Resources on WebLogic Server instances use Java Management Extensions (JMX) Managed
Beans (MBeans) to expose their management functions. An MBean is a concrete Java class that
is developed in accordance with JMX specifications. It can provide getter and setter operations
for each management attribute within a managed resource along with additional management
operations that the resource makes available.
WebLogic Server MBeans that expose the configuration data of a managed resource are called
Configuration MBeans while MBeans that provide performance metrics and other information
about the runtime state of a managed resource are called Runtime MBeans. For example, a
ServerMBean Configuration MBean indicates the listen port for a server instance while the
ServerRuntimeMBean Runtime MBean indicates the current state of a server instance.
While you can create MBeans (custom MBeans) to manage the applications or services that you
deploy on WebLogic Server, the WebLogic SNMP agent does not recognize these custom
MBeans as SNMP managed resources. You cannot configure the WebLogic SNMP agent to
monitor or generate traps for custom MBeans.
For more information about MBeans on WebLogic Server, refer to the following:
z"Understanding WebLogic Server MBeans" in Developing Manageable Applications with
JMX
zWebLogic Server MBean Reference
SNMP MIB for WebLogic Server
All WebLogic Server attributes that can be accessed by SNMP management software are defined
in an SNMP-compliant Management Information Base (MIB).
Note: Not all objects in the WebLogic Server MIB represent MBean attributes. For example,
the WebLogic Server MIB includes objects that define trap variables.
The BEA WebLogic SNMP MIB conforms to a coding standard called Abstract Syntax
Notation.1 (ASN.1). An ASN.1 file is a standard SNMP file that defines the objects that make up
an SNMP-compliant MIB. Each object in the file is defined in compliance with the SNMP
standard. The BEA WebLogic Server software includes the ASN.1 file BEA-
WEBLOGIC-MIB.asn1 for defining the BEA WebLogic Server MIB for SNMP. The BEA
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SNMP MIB for WebLogic Server
WebLogic SNMP Management Guide 1-5
WebLogic SNMP MIB is written in compliance with RFC 1212, as required by the SNMP
standard.
Browsing the MIB
You can use any of the following methods to browse the contents of the WebLogic Server MIB:
zUse a MIB browser. WebLogic Server does not provide a MIB browser, but most vendors
of SNMP utilities do. The MIB is located in a file named
WL_HOME\server\lib\BEA-WEBLOGIC-MIB.asn1.
zUse a Web browser to view the WebLogic Server SNMP MIB Reference on the BEA
e-docs Web site.
Because the MIB Reference uses Javascript and DHTML to provide browsing capabilities
that are similar to a MIB browser, you must use one of the following Web browsers:
– Internet Explorer, version 5 or higher
– Netscape Navigator, version 6 or higher
– Opera 7 or higher
– Mozilla
–Phoenix
Object Identifiers
The WebLogic Server MIB assigns a unique number called an object identifier (OID) to its
MBean attributes. Each MBean attribute in the MIB is an SNMP managed object and is
manageable by an SNMP management system.
The MIB creates a hierarchical relationship between managed objects and expresses the hierarchy
in a tree structure, called the MIB tree or registration tree. Each OID in the MIB consists of a
left-to-right sequence of integers. This sequence defines the location of the object in the MIB tree
and specifies a unique path through the tree to the object. Each node in the path have both a
number and a name associated with it. The path .1.3.6.1.4.1 defines the
private.enterprises OID and each number beneath that node on the tree represents the
branches in the tree reserved for a particular vendor.
The BEA MIBs are registered at the location .1.3.6.1.4.1.140 in the tree. And the WebLogic
Server MIB consists of all OIDs below .1.3.6.1.4.140.625.
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OIDs for Types and Instances
All OIDs that represent WebLogic Server MBean attributes in the WebLogic Server MIB are
identifiers for the MBean attribute type. For example, .1.3.6.1.4.1.140.625.360.1.60 is
the OID for the serverRuntimeState attribute type.
To identify a specific instance of an attribute type, the WebLogic SNMP agent generates and
appends an additional set of numbers to the OID of an attribute type. For example, the OID that
specifies the value of the serverRuntimeState attribute for an active instance of the sample
MedRecServer is
.1.3.6.1.4.1.140.625.360.1.60.32.102.100.48.98.101.102.100.99.102.52.98.97
.48.48.49.102.57.53.51.50.100.102.53.55.97.101.52.56.99.99.97.99
The OID is persistent across instantiations of the object type.
The WebLogic Server MIB Reference appends (.*) to the OIDs that represent attribute types.
This convention indicates that specific instances of the type are identified by additional numbers.
For example, the WebLogic Server MIB Reference indicates that the OID for the
serverRuntimeState attribute type is .1.3.6.1.4.1.140.625.360.1.60(.*).
You can use the snmpwalk or snmpgetnext commands to see the object-instance OID for any
WebLogic Server attribute. For more information, refer to “WebLogic SNMP Agent
Command-Line Reference” in the WebLogic Server Command Reference.
SNMP Community Names
To ensure that the entity requesting data from the WebLogic SNMP agent has permission to
obtain the data, and to verify that the agent has permission to send trap notifications to a target
manager, SNMP uses textual passwords called community names.
When you set up the SNMP agent capability of the Administration Server, one of the things you
must specify is the community name that the agent expects from the SNMP manager. If the agent
receives an SNMP request with an incorrect community name, it generates an
authenticationFailure trap and sends it to the source of the request.
Using Community Names to Specify Target Servers in
Management Requests
You can use some SNMP managers to send requests to the WebLogic SNMP agent for the value
of attributes. Because a WebLogic Server domain can have multiple server instances
concurrently active, a request that specifies only an attribute name is potentially ambiguous. For
example, the attribute serverUptime exists for each WebLogic Server instance in a domain.
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SNMP Community Names
WebLogic SNMP Management Guide 1-7
To request the value of an attribute on a specific Managed Server, when you send a request from
an SNMP manager, append the name of the server instance to the SNMP password (community)
that it sends with the request as follows:
community_prefix@server_name
where community_prefix is the SNMP community name and server_name is the name of the
targeted Managed Server. The community_prefix value sent by the manager must match the
value that you set in the Community Prefix field when you configure the SNMP agent.
To request the value of an attribute on the Administration Server, send a community string to the
WebLogic SNMP agent with the following form:
community_prefix
To request the value of an attribute for all server instances in a domain, send a community string
with the following form:
community_prefix@domain_name
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Introduction to the WebLogic SNMP Agent
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WebLogic SNMP Management Guide 2-1
CHAPTER 2
WebLogic Trap Notifications
You can configure the WebLogic SNMP agent to detect certain thresholds or conditions within
a managed resource and send a report (trap notification) to one or more SNMP managers. The
WebLogic SNMP agent can generate traps that conform to the SNMPv1 or SNMPv2 protocols.
The following sections describe the trap notifications that the WebLogic SNMP agent can
generate:
z“Format of WebLogic Trap Notifications” on page 2-1
z“Automatically Generated WebLogic SNMP Traps” on page 2-3
z“Log Message Traps” on page 2-4
z“Monitor Traps” on page 2-6
z“Attribute Change Traps” on page 2-8
Format of WebLogic Trap Notifications
The WebLogic SNMP agent sends each trap notification to SNMP managers in the form of a
protocol data unit (PDU) with the fields indicated in Figure 2-1.
Figure 2-1 SNMP Trap Packet
PDU
type enterprise agent
address generic
trap
type
specific
trap
type
timestamp variable
bindings
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2-2 WebLogic SNMP Management Guide
The fields have the following meaning:
zPDU type identifies the packet as a trap notification.
zenterprise is the vendor identification (OID) for the systems/network management
subsystem that generated the trap. All traps generated by the WebLogic SNMP agent have
the WebLogic OID .1.3.6.1.4.140.625 in the enterprise field.
zagent address is the IP address of the WebLogic Server instance on which the trap was
generated.
zgeneric trap type is an integer in the range of 0 to 6. Table 2-1 lists the values that the
different types of WebLogic SNMP traps supply for the generic trap type field.
Traps with a generic trap value of 6 are called enterpriseSpecific traps and are
accompanied by a value in the specific trap type field.
zspecific trap type is a number that further qualifies an enterpriseSpecific trap.
Table 2-2 lists the values that the different types of WebLogic SNMP traps supply for the
specific trap type field.
Table 2-1 Values for the Generic Trap Type Field
WebLogic Trap Generated When generic trap type Value
coldStart The Administration Server starts. 0
authenticationFailure An SNMP manager sends an incorrect
community string. The community string
prefix is the actual password and must
match the value that you set in the
Community Prefix field of the
Administration Console. (See “SNMP
Community Names” on page 1-6.)
4
All other WebLogic SNMP traps 6
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WebLogic SNMP Management Guide 2-3
ztimestamp is the length of time between the last re-initialization of the WebLogic SNMP
agent and the time at which the trap was issued.
zvariable bindings consists of name/value pairs that further describe the trap
notification. Subsequent sections in this topic describe the name/value pairs for each type
of trap notification:
–“Automatically Generated WebLogic SNMP Traps” on page 2-3
–“Variable Bindings in Log Message Traps” on page 2-5
–“Variable Bindings in Monitor Traps” on page 2-8
–“Variable Bindings in Attribute Change Traps” on page 2-9
Automatically Generated WebLogic SNMP Traps
If you enable the SNMP service for a domain, the WebLogic SNMP agent generates the trap
notifications described in Table 2-3. Some of these traps include name/value pairs in the PDU to
further describe the event.
Table 2-2 Values for the Specific Trap Type Field
WebLogic Trap Generated When specific trap
type Value
All Log Message Traps A server instance logs a message that matches
user-defined criteria for sending a log
notification trap.
60
serverStart Trap A Managed Server that was down is now up. 65
serverShutDown Trap A Managed Server that was up is now down. 70
All Monitor Traps A user-defined JMX monitor detects the crossing
of a threshold or occurrence of an event. 75
All Attribute Change Trap An attribute selected by the user has changed in
value. 80
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2-4 WebLogic SNMP Management Guide
Log Message Traps
Subsystems and deployable modules (such as applications) on a WebLogic Server instance
generate log messages to communicate status or other operational data.
Each server instance saves these messages in a local log file and then broadcasts them as JMX
notifications. You can set up the WebLogic SNMP agent to listen for all of these messages or you
can set up a filter based on criteria such as the following:
zThe severity level of the message
zThe name of the subsystem that generated the message
zThe user ID under which the subsystem is running
zA unique message ID
zA string within the message text
For example, you can specify that only messages from the Security Service of severity level
ERROR or higher are sent to the SNMP agent.
Table 2-3 Automatically Generated Trap Notifications
Trap Generated When Variable Bindings
coldStart The Administration Server starts. none
authenticationFailure An SNMP manager sends an
incorrect community string. The
community string prefix is the actual
password and must match the value
that you set in the Community Prefix
field of the Administration Console.
(See “SNMP Community Names” on
page 1-6.)
none
serverStart A WebLogic Managed Server that
was down is now up. Contains two name/value pairs to
identify server start time and the
server name.
serverShutDown A Managed Server that was up is now
down. Contains two name/value pairs to
identify server down time and the
server name.
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Log Message Traps
WebLogic SNMP Management Guide 2-5
When the agent receives a message, it generates an SNMP log notification trap. (See Figure 2-2.)
Figure 2-2 Log Message Traps
Variable Bindings in Log Message Traps
This section describes the name/value pairs that the log message traps pass to the SNMP manager
in the variable bindings field:
ztrapTime — Time when the trap is generated.
ztrapServerName — Name of the server instance on which the log message was
generated.
ztrapMachineName — Name of the machine on which the server instance is running.
ztrapLogThreadId — Thread ID from the log message.
Managed Server
Log Broadcaster
Local
Log File
Administration Server
SNMP Agent
Subsystem
Application Log Publisher
Filter
PDU
type enterprise agent
address generic
trap
type
specific
trap
type
timestamp variable
bindings
SNMP Trap
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ztrapLogTransactionId — Transaction ID, if any, from the log message. Transaction ID
is present only for messages logged within the context of a transaction.
ztrapLogUserId — The user ID from the log message. The user ID indicates the security
context in which the log message was generated.
ztrapLogSubsystem — The subsystem that generated the log message.
ztrapLogMsgId — The log message ID from the log message.
ztrapLogSeverity — The message severity level from the log message.
ztrapLogMessage — The text of the log message.
For more information on log messages and the WebLogic Server logging subsystem, refer to
"Understanding WebLogic Logging Services" in Configuring Log Files and Filtering Log
Messages.
Monitor Traps
To periodically check the value of WebLogic resources for changes, you set up monitors and
assign them to instances of WebLogic Server. The monitors poll the MBeans of WebLogic
resources at a specified interval and send notifications to the WebLogic SNMP agent when an
event that you specify occurs, such as the crossing of a threshold. The SNMP agent generates a
trap notification and sends it to the SNMP managers. (See Figure 2-3.)
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Figure 2-3 Monitor Traps
If you are unfamiliar with WebLogic Server MBeans, refer to "Understanding WebLogic Server
MBeans" in Developing Manageable Applications with JMX.
You can configure three types of JMX monitors, depending on the data type of the attribute that
you want to observe (the MBean Javadoc describes the type of data that its attributes return):
zCounter Monitor
A counter monitor observes attribute values that are returned as an Integer object type.
You can specify that a trap is generated if an attribute is beyond the bounds of a threshold
value. You can also specify that if a value exceeds a threshold, the monitor increases the
threshold by an offset value. Each time the observed attribute exceeds the new threshold,
the threshold is increased by the offset value, up to a maximum allowable threshold that
you specify.
Managed Server
Administration Server
SNMP Agent
Resource
PDU
type enterprise agent
address generic
trap
type
specific
trap
type
timestamp variable
bindings
The agent sends an
Monitors
Monitors periodically
poll attributes of MBeans.
Each monitor polls
a single attribute.
When a event of interest occurs,
the monitor sends a JMX
notification to the SNMP agent.
SNMP Trap to SNMP managers.
MBeans
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zGauge Monitor
A gauge monitor observes changes in MBean attributes that are expressed as integers or
floating-point.
You can specify that a trap is generated if an attribute is beyond the bounds of a high or
low threshold value.
zString Monitor
A string monitor observes changes in attributes that are expressed as String objects.
You can specify that a trap is generated if there is a match between the value and the string
you provide, or you can specify that the trap is generated if the value differs from the string
you provide.
Variable Bindings in Monitor Traps
A JMX monitor polls for a specified threshold or condition and the agent generates a monitor trap
when the specified threshold is crossed, or the specified condition occurs. The WebLogic SNMP
agent includes the following name/value pairs in the variable bindings of each monitor trap:
ztrapTime — The time at which the trap was generated.
ztrapServerName — The local server whose attribute value generated the trap.
ztrapMonitorType — Either CounterMonitor, StringMonitor, or GaugeMonitor.
ztrapMonitorThreshold — An ASCII representation of the threshold that triggered the
trap.
ztrapMonitorValue — An ASCII representation of the value that triggered the trap.
ztrapMBeanName — The name of the MBean that contained the attribute being monitored.
ztrapMBeanType — The type of the MBean that contained the attribute being monitored.
ztrapAttributeName — The name of the attribute whose value triggered the trap.
Attribute Change Traps
While you can use JMX monitors to periodically poll WebLogic Server resources for changes to
attributes that exceed the bounds of specific thresholds, you can also configure the SNMP agent
to send a trap immediately after an attribute is changed in any way. For example, you can use a
monitor to poll for changes in the current number of active JDBC pools. If the number of active
pools exceeds a threshold, the SNMP agent can send a trap. You would use an attribute change
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trap to detect whether an attribute such as the name of a JDBC pool or the listen port has been
changed.
Variable Bindings in Attribute Change Traps
An attribute change trap notification includes the following name/value pairs in the variable
bindings:
ztrapTime — The time at which the trap was generated.
ztrapServerName — The name of the Administration Server.
ztrapMBeanName — Name of the MBean that includes the attribute.
ztrapMBeanType — Type of the MBean that includes the attribute.
ztrapAttributeName — Name of the configuration attribute that has changed.
ztrapAttributeChangeType — The value can be either ADD, REMOVE, or UPDATE.
ztrapAttriruteOldVal — Value of the attribute before the change.
ztrapAttributeNewVal — Value of the attribute after the change.
Note: Creation of monitors for changes in run-time attributes is not supported. Only attributes
in the configuration MIB can be monitored for change of attribute value.
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WebLogic SNMP Management Guide 3-1
CHAPTER 3
SNMP Proxies
This section provides background information on WebLogic Server and SNMP proxy agents.
SNMP Agent as Proxy for Other Agents
The original SNMP management model allowed for only a single, monolithic agent to carry out
all management responsibilities on a given network node (IP address). This solution was not
flexible enough to provide for effective management of increasingly complex systems. In
addition to the agents typically provided by computer manufacturers for hardware and operating
system information, agents are also produced by vendors of other products, such as agents for
SQL database systems. Complex and heterogeneous systems thus require the ability to
accommodate multiple agents on a single network node.
This weakness of the original SNMP model led to the concept of an SNMP master agent that acts
as a proxy for other SNMP agents. The WebLogic SNMP agent can function as a master agent in
this sense. To use the master agent functionality of the WebLogic SNMP agent, you can assign
branches of the registration tree (OID tree) as the responsibility of other SNMP agents. Each of
these will be a branch that encompasses the private MIB (or some part of that MIB) which the
target agent is designed to manage.
Note: You cannot use the WebLogic SNMP agent as a proxy for SNMP agents in other
WebLogic Server domains. For example, WebLogic domainA's SNMP agent cannot
proxy requests to domainB's SNMP agent. This limitation is in effect because all
WebLogic SNMP agents use the same MIB root.
Instead of proxying requests to multiple WebLogic Server domains, you can place all of
your server instances in a single domain and send requests directly to each Managed
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Server. See “Using Community Names to Specify Target Servers in Management
Requests” on page 1-6.
The WebLogic SNMP agent listens for requests from SNMP managers and then fans out these
requests to other SNMP agents on the Administration Server machine, if the attribute requested
has an OID falling under the branch of the OID tree assigned to one of those other agents. By
default the WebLogic SNMP agent listens for management requests on port 161. If the WebLogic
SNMP agent is to proxy for other SNMP agents, then those other agents must be configured to
listen for SNMP management requests on a port other than the port that the WebLogic SNMP
agent is using to receive requests from SNMP managers.
The Microsoft Windows SNMP Service
While the WebLogic Server SNMP agent can be a proxy for other SNMP agents, it cannot be
configured as a subagent of the Microsoft Windows SNMP agent service.
Using Microsoft Extension Agent API, the Microsoft Windows 2000 SNMP agent service can be
a proxy for other SNMP agents. However, WebLogic Server does not support this feature and
cannot use the Windows SNMP agent as a proxy.
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APPENDIX A
Sources of SNMP Information
This appendix lists sources of additional information about Simple Network Management
Protocol, including the following:
zReference Books
zStandards and Drafts
zObtaining RFCs
Reference Books
If you need additional information about MIBs, agents, or the SNMP protocol, refer to these
books:
zComer, Douglas; Internetworking with TCP/IP, Vol. 2; Prentice-Hall, Englewood Cliffs,
New Jersey, 1991
zLeinwand, Allan and Fang, Karen; Network Management: A Practical Perspective;
Addison-Wesley, Reading, Massachusetts, 1993
zRose, Marshall T.; The Simple Book: An Introduction to Management of TCP/IP-based
Internets; Prentice-Hall, Englewood Cliffs, New Jersey, 1991
zRose, Marshall T.; The Open Book: A Practical Perspective on Open Systems
Interconnection; Prentice-Hall, Englewood Cliffs, New Jersey, 1989
zMiller, Mark; Managing Internetworks with SNMP, M & T Books
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4-2 WebLogic SNMP Management Guide
zStallings, William; SNMP, SNMPv2 and CMIP: The Practical Guide to Network
Management Standards, Addison-Wesley, Reading, Massachusetts, 1993
Standards and Drafts
The SNMP protocol has been defined through a series of Requests for Comments (RFCs). The
following standards and drafts are available.
Figure 0-1 SNMP RFCs
RFC Number Description
052 IAB Recommendations
1089 SNMP over Ethernet
1109 Ad-hoc Review
1155 Structure of Management Information
1156 Management Information Base (MIB-I)
1157 SNMP Protocol
1161 SNMP over OSI
1187 Bulk table retrieval
1212 Concise MIB definitions
1213 Management Information Base
(MIB-II)
1214 OSI MIB
1215 Traps
1227 SNMP Multiplex (SMUX)
1228 SNMP-DPI
1229 Generic-interface MIB extensions
1230 IEEE 802.4 Token Bus MIB
1231 IEEE 802.5 Token Ring MIB
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WebLogic SNMP Management Guide 4-3
Obtaining RFCs
You can obtain Requests for Comments in the following ways:
zDownload them from almost anywhere on the Internet
zObtain them from SRI International
Mailing Address: SRI International, EJ291, DDN Network Information Center, 333
Ravenswood Ave., Menlo Park CA 94025
Phone: +1.800.235.3155
e-mail: MAIL-SERVER@nisc.sri.com. Leave the subject field blank. In the body, enter:
SEND RFCnnnn.TXT-1
FTP: ftp://ftp.nisc.sri.com/rfc/rfcNNNN.txt
1239 Reassignment of MIBs
1243 AppleTalk MIB
1248 OSPF MIB
ISO 8824 ASN.1
ISO 8825 BER for ASN.1
RFC Number Description
BETA
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4-4 WebLogic SNMP Management Guide
BETA
WebLogic SNMP Management Guide Index-1
Index
A
administration domain. See domain 1-2
Administration Servers
defined 1-2
agent
what it is 1-2
agents
what they are 1-2
attribute change trap
variable bindings in 2-9
C
community name, SNMP 1-6
how manager must specify 1-7
community prefix
see community name 1-7
Configuration MBeans
defined 1-4
See also Local Configuration MBeans and
Administration MBeans
customer support contact information viii
D
documentation, where to find it vii
domains
defined 1-2
E
enterprise OID 2-2
F
format, SNMP trap notification 2-1
G
generic trap types 2-2
J
Java Management Extension
See JMX 2-7
JMX monitors 2-7
variable bindings in attribute change trap 2-9
variable bindings in monitor trap 2-8
L
log message traps
variable bindings in 2-5
M
managed object
in SNMP 1-2
managed resource
what it is 1-2
Managed Servers
defined 1-2
MBeans
defined 1-4
MIB file
location of 1-5
MIB, for WebLogic 1-4
monitor trap
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Index-2 WebLogic SNMP Management Guide
variable bindings in 2-8
multiple SNMP agents
configuring WebLogic agent with 3-1
P
polling
how to offload to WebLogic Administration
Server 2-6
printing product documentation vii
proxying for other agents 3-1
R
Runtime MBeans
defined 1-4
S
serverStart trap 2-4
SNMP
agent/manager model in 1-2
trap notification, fields in 2-1
SNMP agent
configuring as proxy agent 3-1
SNMP agent, WebLogic
what it does 1-3
specific trap types
for WebLogic 2-2, 2-3
support
technical viii
T
trap notification
what it is 1-2
traps based on log messages 2-4
V
variable bindings
in attribute change trap 2-9
in log message trap 2-5
in monitor trap 2-8, 2-9
W
WebLogic
specific trap types 2-2, 2-3
WebLogic enterprise OID 2-2

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