The Webserver and the availability/info branches are shown in the Investigator but not the performance branch.

Products

• CA Application Performance Management Agent (APM / Wily / Introscope)
• INTROSCOPE

Issue/Introduction

 The Webserver is visible in the Investigator but only the availability and info branches are visible when using the Webserver PowerPack to monitor Apache Web Server. There is no performance branch.

Environment

Webserver PowerPack for Apache from 10.7 onward.

Cause

There are a couple of possible causes for this issue, and corrective action will depend on the type of error reported.

First, check the agent log file to verify that it is attempting to obtain performance data. The log will contain an error similar to the following:

• [ERROR] [WebServerMonitor] Could not get performance metrics from server : https://##.##.##.##:443/server-status?auto

Next, check the webserver logs to see if any error is reported in the request to access the page identified above.

Resolution

 Scenario 1:

 

 If the following type of error is seen:

 

• [error] [client <client_number>] File does not exist: /opt/mywebserver/data/server-status

 

it can indicate that the page has not been enabled in the httpd.conf file.

 

 To resolve this, ensure that the following entry exists and is not commented out:

 

• LoadModule status_module modules/mod_status.so

 

 Scenario 2:

 

 If the following type of error is reported:

 

• [error] [client <client_number>] client denied by server configuration: /data/mywebserver/data/server-status

 

it can indicate that the httpd.conf file has not been configured to grant permission to access this page from the address of the webserver agent.

 

 To resolve the problem, the page must be included in the Allow from list as shown:

 

 

 

 	<Location /server-status>
 	SetHandler server-status
 Order deny,allow
 Deny from all
 Allow from .mydomain.com
 Allow from ##.##.##.##
 </Location>

 

 

 

 To get more information about the nature of the problem enable DEBUG logging in the webserver agent by setting:

 

log4j.logger.WebServerMonitor=DEBUG, logfile

 

in the file WebServerAgent.profile

 

• [ERROR] [WebServerMonitor] Could not get performance metrics from server : https://##.##.##.##:443/server-status?auto
• [DEBUG] [WebServerMonitor] 403 is the Status for : https://##.##.##.##:443/server-status?auto

 

 This example of DEBUG logging reveals an underlying HTTP 403 error (permission denied) which matches the second scenario. An underlying HTTP 404 error (not found) would point to the first scenario.