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Working With Alerts

Sep 18, 2010 15:19

Matt Brandabur

Oct 05, 2010 21:07

Mulesoft Tcat Server Documentation

Working With Alerts

Mulesoft Documentation Page

Contents

Working With Alerts

Alerts give you visibility to events that might need your attention and allow you to notify other administrators about actions they need to take. Alerts can be triggered on several different things:

  • A server going down
  • Web application statistics, such as average processing time
  • Regular expressions in log files
  • URL status check
  • JMX attributes which match certain threshold criteria

When an alert occurs, a pop-up appears briefly and indicates that the alert condition occurred. You can also configure various alert destinations, such as an email address or an SNMP trap target.

Overview of Alerts

Click the Alerts tab to manage and view alerts. Use the navigation tree on the left to view raised alerts (that is, alerts that have been triggered), alert definitions, destinations, and notifications. Use the same nodes to manage alerts, destinations, and notifications. When you first click the Alerts tab, the pane displaying raised alerts appears.

Viewing Raised Alerts

Click the View raised alerts node in the navigation tree on the left to view alerts that have been triggered. The details pane displays a table with summary information about each alert, plus icons that indicate the severity of the alert. Alerts that have not yet been read appear bolded, as shown in the figure below. In addition, the number of unread alerts appears highlighted in red at the top of the pane.

The details pane shows the following information about each alert:

  • Severity of the alert. The severity of an alert is set when the alert is created, and can be one of the following: Fatal, Critical, Major, Minor, Information.
  • Server on which the alert occurred
  • Name of the alert
  • Summary information about the alert, such as low memory alert
  • Time stamp indicating the date and time the alert was raised

Click anywhere on an alert row to select that alert and mark that alert as read. You can also click the Mark as Read button to mark checked alerts as read, or click the Delete button to delete checked alerts. Once an alert is read, its font changes from bold to plain.

The icons to the left of each alert indicate the severity of the alert. Hover the mouse over these icons to see what they represent. Briefly, the icons indicate the following

  • The letter "i": Information alert
  • Down arrow on blue background: Minor alert
  • Up arrow on yellow background: Major alert
  • Up arrow on orange background: Critical alert
  • Fire icon on red background: Fatal alert

New Alerts Notification

The Alerts screen displays a message in red at the top notifying you of the number of alerts that have not yet been read. This notification about unread alerts appears at the top of all console panes. In addition, when an alert is triggered, a pop-up appears briefly indicating the alert that was triggered. You see this pop-up regardless of the pane you are currently viewing. The new alert also increments the unread alerts counter, assuming you haven't yet looked at that alert. In addition to incrementing the counter, a note appears indicating the number of new alerts just added.

Click the notification of unread alerts, circled in red in the figure below, to open the pane to view alerts.

TODO: screenshot

When the pane displaying raised alerts opens, notice that any unread alerts appear in bold font at the top of the pane. Alerts that have already been read are in plain font at the bottom of the pane, and the counter of unread alerts is decremented. The number of newly added alerts is also noted. Click an alert to read it.

Defining Alerts

Click the "Alert Definitions" node in the navigation tree to see all alerts currently set up. From this pane, you can create new alerts and edit details about existing alerts. The figure below illustrates the details pane for viewing and managing alerts. The pane displays a summary of the existing alerts and provides buttons for adding new alert definitions, controlling alerts, and deleting them.

The details pane lists all currently set alerts and displays the following information about each alert:

  • The name of the alert
  • A description of the alert
  • The alert severity level (Fatal, Critical, Major, Minor, Information)
  • The type of the alert (such as Low Memory, Server Down, Webapp Processing Time, etc). Y
  • The identity of the server for which the alert applies, if any.
  • The current alert status (Active, Disabled).

Creating a New Alert

Click the New Alert button to create a new alert. The Add Alert pane displays a Type field. From the Type field's pull-down list, select the alert type.

Following are the names of the alert types and a description of the criteria they can be configure to fire on:

Type

Description

JMX Attribute

A JMX attribute exceeds, goes below, or matches a particular value

Log Regex

A line in a selected log file matches a particular regular expression

Low Memory

A JVM memory pool exceeds a threshold.

Server Down

A server goes offline or becomes unresponsive.

Server Up

A server comes online.

URL Health

Checks URLs periodically to ensure that they are available on the network.

Webapp Average Processing Time

Average request processing time for a web application.

Webapp Average Requests/second

Average requests per second for a web application.

Webapp Error Count

The number of errors in a one minute interval for a web application.

Note: Currently, low memory alerts are not supported in an OpenJDK environment.

Once you select the alert type, the pane expands to display additional fields to which you enter data describing the alert. Different alert types have different data fields. The Add Alert pane displays the appropriate fields for the alert type you selected and you then enter the required and optional data. For example, the following figure shows the Add Alert pane for the Server Down alert type.

Enter a name for the alert and, optionally, a description. From the Severity pull-down list, select the severity level (Fatal, Critical, Major, Minor, Information) of the alert. For the Server field, select the server(s) to which the alert applies (the default is none), and then check if the alert is active. A field for which data is required is marked with an exclamation point (warning) and highlighted in red if left blank. (The figure below has a field marked as required.) For more information on these fields, see below.

The figure below shows a sample entry for a server down alert type. Once you select Server Down for the alert type, the screen expands and displays the additional fields of data you must enter. While Description is optional, you must select or enter data for the other fields. Click Save to save the new alert, or Cancel to quit without saving the alert.

The following explains the data you might select or enter for particular fields when setting up an alert.

Common Alert Fields

As explained previously, different alert types may prompt you for different data fields. Most alerts, regardless of type, include the following generic fields:

  • Server - The server that this alert will be applied to.
  • Severity - The severity of an alert is set when the alert is created, and can be one of the following: Fatal, Critical, Major, Minor, Information.
  • Active - whether or not the alert is currently active, if no, no alerts will be triggered for this definition.

JMX Attribute

Configures an alert which fires if a JMX attribute value exceeds, goes below or equals a certain value.

  • MBean and attribute - the MBean name and attribute value that is monitored. Click "Browse" to view the MBean tree and select an attribute.
  • Comparison - > (greater than), < (less than), or = (equals to).
  • Value - the value that will be used in the comparison to determine if this alert will fire.
  • Period - how often in milliseconds the value is checked.

Log Regex

Configures an alert which monitors file changes for a particular regular expression.

  • Log Files - a wildcard expression, such as "logs/*.log", which configures which log files to monitor. The directory is resolved relative to CATALINA_HOME.
  • Regular Expression - The regular expression to look for in the log files. For instance, type "SEVERE" to find all SEVERE log warnings.

Low Memory

Configures an alert which monitors a specified memory pool to see if it exceeds a particular threshold percentage.

  • Memory Pool - The memory pool to monitor, such as Total or PermGen.
  • Threshold Percentage - the percentage of memory pool utilization that must be reached before firing the alert.

Server Down

Configures an alert which fires if a server goes down or becomes unresponsive. No extra configuration options.

Server Up

Configures an alert which fires if a server comes online. No extra configuration options.

URL Health

Configures an alert which monitors the status of a URL. Useful for monitoring whether a particular public URL is accessible.

  • URL - the URL to check periodically.
  • Status Code - the expected HTTP status code
  • Period - the period, in seconds, with which to check the URL.

Webapp Average Processing Time

Configures an alert which monitors the average request processing time for a web application. This value is recomputed every minute.

  • Application - the web application to check. Select "All" to monitor the request time across all applications.
  • Comparison - > (greater than), < (less than), or = (equals to).
  • Value - the value that will be used in the comparison to determine if this alert will fire.

Webapp Average Requests/second

Configures an alert which monitors the average requests per second for a web application. This value is recomputed every minute.

  • Application - the web application to check. Select "All" to monitor the requests per second across all applications.
  • Comparison - > (greater than), < (less than), or = (equals to).
  • Value - the value that will be used in the comparison to determine if this alert will fire.

Webapp Error Count

Configures an alert which monitors the error count in the last minute for a web application. This value is recomputed every minute.

  • Application - the web application to check. Select "All" to monitor the error count across all applications.
  • Comparison - > (greater than), < (less than), or = (equals to).
  • Value - the value that will be used in the comparison to determine if this alert will fire.

Editing an Alert

Click the alert name in the Manage Alerts summary pane. The pane displays the data previously entered for the alert, in the same format used for creating an alert, and you can make the desired changes.

Note that you cannot change the name of an alert. If you need to change the name of the alert, you should delete it and re-create it with the new name.

For more information on alert fields, see below.

Managing Alerts

To manage alerts, click the alert to select it. A checkmark appears in the alert's checkbox when selected. Use the Control button to either activate or disable the selected alert(s). Use the Delete Alert button to delete the selected alert(s). Before alerts are actually deleted, a dialog prompts you to confirm the deletion.