Well done Bill, this is good stuff:)
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bill
Burke
Sent: Friday, December 12, 2003 4:24 PM
To: Jboss-Dev; JBoss 2; [EMAIL PROTECTED]
Subject: [JBoss-dev] New JBoss Monitoring services
This will be released in JBoss 3.2.4, but it is now available in 3.2
branch: cvs checkout -r Branch_3_2 jboss-3.2
I've also attached some screen shots
JBoss Monitoring
In JBoss 3.2.4, we've implemented some new JMX MBean monitoring and a
nice GUI around this infrastructure as well as a way to plug in how
alerts are processed. Why didn't we use the JMX Gauge and String
monitors that come implemented with the JMX spec? 3 reasons:
1. They are not integrated with our Service architecture
2. They have no way of determining which monitors have sent an alert and
are currently disabled because an alert was reached
3. They have no way of reseting an alert
So, what infrastructure have we built? First let's look at configuring
a JMX MBean monitor through the plain old -service.xml interface that
you would to create any MBean.
All Monitors are MBeans that start a thread to watch the values of
another MBean's attribute. When a monitoring threshold is reached, the
MOnitor will send out an MBean Notification to a set of registered
listeners. Currently in JBoss, the are two types of listeners, a dumb
Console listener, and an Email listener which will send out an email
whenever an alert is received. Of course, the messages are fully
configurable.
Numeric Attribute Monitors
The first type of monitor is a org.jboss.monitor.ThresholdMonitor that
is used to track Numberic MBean attributes. Here is an example
configuration of a monitor of free available memory. It will send a JMX
Notification when free memory goes below one megabyte. The MBean it is
watching over that has this particular stat is
jboss.system:type=ServerInfo.
File: FreeMemory_Monitor-service.xml
<?xml version="1.0" encoding="UTF-8"?>
<server>
<mbean code="org.jboss.monitor.ThresholdMonitor"
name="jboss.monitor:service=FreeMemory">
<attribute name="MonitorName">FreeMemory Monitor</attribute>
<attribute
name="ObservedObject">jboss.system:type=ServerInfo</attribute>
<attribute name="ObservedAttribute">FreeMemory</attribute>
<attribute name="Threshold">1000000</attribute>
<attribute name="CompareTo">1</attribute>
<attribute name="Period">1000</attribute>
<attribute name="Enabled">true</attribute>
<depends-list optional-attribute-name="AlertListeners">
<depends-list-element>jboss.alerts:service=ConsoleAlertListener</depends
-list-element>
<depends-list-element>jboss.alerts:service=EmailAlertListener</depends-l
ist-element>
</depends-list>
</mbean>
</server>
Let's walk through each attribute:
<attribute name="MonitorName">FreeMemory</attribute>
The display name in which this monitor will be shown in the web-console.
If you create monitors by hand you can have it managed by the
web-console if you have one monitor defined in one file only and the
name of the file is the same name as the monitor and the file lives in
./deploy/management/monitors/ So The above example the filename should
be FreeMemory_Monitor-service.xml, notice that whitespace is substituted
with an '_' charater.
<attribute
name="ObservedObject">jboss.system:type=ServerInfo</attribute>
<attribute name="ObservedAttribute">FreeMemory</attribute>
These are the MBean and the MBean attribute this monitor will watch. If
the MBean is a ServiceMBean then you should make this a <depends
optional-attribute> so that this monitor doesn't start before the
watched MBean is loaded.
<attribute name="Threshold">1000000</attribute>
<attribute name="CompareTo">1</attribute>
The Threshold is the value threshold of the attribute. The CompareTo is
a numeric value, -1 means > (greater than), 0 means = (equal), 1 means
(less than). These are the same values used by Java comparators. So in
this example, when the FreeMemory attribute is less than 1000000 a JMX
notification will be sent.
<attribute name="Period">1000</attribute>
The MBean creates a thread that will wake up every so often to check the
threshold against the MBean attribute it is watching. The Period is the
time in milliseconds this thread will sleep.
<attribute name="Enabled">true</attribute>
Enabled determines whether or not this monitor should actually monitor.
It is the on/off switch of the monitor.
<depends-list optional-attribute-name="AlertListeners">
<depends-list-element>jboss.alerts:service=ConsoleAlertListener</depends
-list-element>
<depends-list-element>jboss.alerts:service=EmailAlertListener</depends-l
ist-element>
</depends-list>
When the threshold is triggered, the Monitor will send JMX NOtification
to all registered listeners. For this particular MOnitor, a Console and
Email listener have been registered. We'll look into how to configure
the Email and Console listener in a bit, but when a threshold is
breached, a message will be sent to the JBoss console (System.out via
the ConsoleAlertListener) and via an Email with the EmailAlertListener.
That's it!
StringThresholdMonitor
You can also monitor string values:
<?xml version="1.0" encoding="UTF-8"?>
<server>
<mbean code="org.jboss.monitor.StringThresholdMonitor"
name="jboss.monitor:service=BindAddress_Monitor">
<attribute name="MonitorName">BindAddress Monitor</attribute>
<depends
optional-attribute-name="ObservedObject">jboss:service=Naming</depends>
<attribute name="ObservedAttribute">BindAddress</attribute>
<depends-list optional-attribute-name="AlertListeners">
<depends-list-element>jboss.alerts:service=ConsoleAlertListener
</depends-list-element>
</depends-list>
<attribute name="Threshold">0.0.0.0</attribute>
<attribute name="Period">1000</attribute>
<attribute name="EqualityTriggersAlert">true</attribute>
<attribute name="Enabled">true</attribute>
</mbean>
</server>
The config is the same as Threshold except that there is an
"EqualityTriggersAlert" attribute. If this is true and the attribute
equals the Threshold value, then an alert will be triggered
EmailAlertListener
To configure email you must
1) Configure ./deploy/mail-service.xml to work with your mail server
2) Edit ./deploy/monitoring-service.xml and uncomment out the
EmailAlertListener:
monitoring-service.xml:
<server>
<mbean code="org.jboss.monitor.alerts.ConsoleAlertListener"
name="jboss.alerts:service=ConsoleAlertListener">
<attribute name="MessageTemplate"><![CDATA[%(MONITOR_NAME) was
triggered for attribute %(ATTRIBUTE).]]></attribute>
<attribute name="AlertName">Console Alert</attribute>
</mbean>
<!-- Enable after filling in correct to, from, and reply to
<mbean code="org.jboss.monitor.alerts.EmailAlertListener"
name="jboss.alerts:service=EmailAlertListener">
<depends>jboss:service=Mail</depends>
<attribute name="AlertName">Email Alert</attribute>
<attribute name="To">[EMAIL PROTECTED]</attribute>
<attribute name="From">[EMAIL PROTECTED]</attribute>
<attribute name="ReplyTo">[EMAIL PROTECTED]</attribute>
<attribute name="SubjectTemplate"><![CDATA[[jboss-alert]
%(MONITOR_NAME)]]></attribute>
<attribute name="MessageTemplate"><![CDATA[%(MONITOR_NAME) was
triggered for attribute %(ATTRIBUTE).]]></attribute>
</mbean>
-->
</server>
Let's walk through each attribute of the email listener.
<attribute name="AlertName">Email Alert</attribute>
This is the display name of the Listener within the web-console gui.
<attribute name="To">[EMAIL PROTECTED]</attribute>
<attribute name="From">[EMAIL PROTECTED]</attribute>
<attribute name="ReplyTo">[EMAIL PROTECTED]</attribute>
Are the email addresses. "To" can be multiple emails comma delimited.
From and ReplyTo must be a single email address.
<attribute name="SubjectTemplate"><![CDATA[[jboss-alert]
%(MONITOR_NAME)]]></attribute>
<attribute name="MessageTemplate"><![CDATA[%(MONITOR_NAME) was
triggered for attribute %(ATTRIBUTE).]]></attribute>
The SubjectTemplate is the string template for the Email Subject. The
MessageTemplate is a string template for the Email message body. There
are some substitution characters you can use:
For System Properties you can use the standard MBean service subtition
of
${some.system.property}
There are also some Monitoring-specific substitions via a different
delimeter:
%(MONITOR_NAME)
The thing referenced within the %(...) parens will be transfered to one
of these values:
OBSERVED_OBJECT - the MBean ObjectName that is being monitored
MONITOR_OBJECT_NAME - the JMX ObjectName of the monitor itself
MONITOR_NAME - the Display Name of the Monitor
ATTRIBUTE - the attribute name of the MBean being
observed
TRIGGERED_ATTRIBUTE_VALUE - The value that cause the alert trigger
THRESHOLD - The value of the threshold
There is also a GUI for monitoring through the JBoss Management Console
accessed at http://host:8080/web-console. If you go to the System tree
and click down to the JMX view on a particular MBean, open that up and
you should see a list of attributes. Right click on an attribute should
give you a menu list of "graph" and "create monitor", select "create
monitor" and you will be brought to the creation screen. Monitors will
show up under the Monitors tree item in the management console.
--
================
Bill Burke
Chief Architect
JBoss Group LLC.
================
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