If you installed the Apache Agent and are experiencing problems, try these troubleshooting suggestions.

Undefined Symbol Error

An error message similar to the following typically indicates that you have loaded the incorrect agent library for the version of Apache you are using. 

ERROR
httpd: Syntax error on line 953 of /srv/jas/app/embcms/HTTPServer/cma1-dev2/conf/httpd.conf: Syntax error on line 7 of /srv/jas/app/embcms/HTTPServer/cda0-dev2/conf/appdynamics.conf: Cannot load /srv/jas/data/AppDynamics/WebAgent/WebServerAgent/Apache/libmodappdynamics.so into server: /srv/jas/data/AppDynamics/WebAgent/WebServerAgent/Apache/libmod_appdynamics.so: undefined symbol: ap_log_error

Check the description of LoadModule on Install the Apache Agent to make sure that you are loading the correct module. For example, for Apache 2.2, your LoadModule directive should be:

LoadModule appdynamics_module /srv/jas/data/AppDynamics/WebAgent/ApacheAgent/Apache/libmod_appdynamics22.so

App Crash Caused by libstdc++ Mismatch

The AppDynamics agent uses libstc++ v6. If your application uses a different version of libstc++ and the modules were not loaded in the correct order, the wrong library routines could be called. If you get a dump with a long stack trace, this could be the cause. See Apache with libstdc++5 Considerations for information on how to prevent this.

Tier Name Not Specific to the Apache Agent

When the Apache Agent and Machine Agent are hosted on the same server, and the Machine Agent is started before the Apache Agent, then the tier is registered as a Java tier that prevents the Apache Agent from registering itself. 

An error message is displayed in the Apache Agent logs:

Is your agent attempting to register to the wrong tier?

Workaround

  1. Stop the Machine Agent and Apache Agent.
  2. Delete the tier from the Controller UI.
  3. Restart the Apache Agent first and allow it to register the tier.
  4. Restart the Machine Agent.