Issue while instrumenting Oracle HTTP Server (OHS) on Solaris

[bhaveshbjoshi]

Summary

This article describes a scenario where Oracle HTTP Server (OHS) running on Solaris is not detected or deep monitored by Dynatrace OneAgent. Although WLST-related processes may appear in Dynatrace, the actual OHS (httpd.worker) process isn't instrumented and therefore does not produce service visibility or distributed traces.

This article explains how to identify the issue and configure Oracle HTTP Server so that OneAgent can successfully instrument the OHS process.

Problem

Oracle HTTP Server (httpd.worker) is not detected in Dynatrace. Only WebLogic Node Manager or WLST-related processes appear in Dynatrace; however, they don't provide application traces because the actual OHS process isn't instrumented.

Customers may observe the following:

• OHS (httpd.worker or ohs*) is missing from Dynatrace.
• Adding Dynatrace LD_PRELOAD_64 variables to startup script only results in monitoring of parent processes and not the actual OHS process.

Troubleshooting steps

 

1. Verify the OHS process environment

Identify the OHS process and inspect its environment:

pargs -e <httpd_worker_pid>

If the Dynatrace preload variables are missing, the OHS process isn't being started with the required OneAgent configuration.

2. Check for legacy Apache module configuration

Review httpd.conf for entries similar to:

LoadModule oneagent_module /opt/dynatrace/oneagent/agent/bin/solaris-sparc-64/liboneagentloader.so

If present, remove them and restart the service.

Resolution

The Dynatrace preload variables should be configured through the Oracle HTTP Server property files instead of the startup scripts.

An Oracle HTTP Server administrator (OHS SME) may be required to help identify the correct files and apply the configuration.

Oracle-documentation: https://docs.oracle.com/middleware/1212/webtier/HSADM/property_files.htm#HSADM1198

The files to be modified are usually located under:

DOMAIN_HOME/config/fmwconfig/components/OHS/

Common OHS property files include:

• ohs_admin.properties
• ohs_nm.properties
• ohs.plugins.nodemanager.properties

The environment property syntax is:

environment[.append][.<order>].<name> = <value>

Example configuration:

environment.DT_HOME=/opt/dynatrace/oneagent
environment.LD_PRELOAD_64=$DT_HOME/agent/lib64/liboneagentproc.so
environment.LD_PRELOAD=$DT_HOME/agent/lib/liboneagentproc.so

Add the applicable Dynatrace environment variables to the appropriate OHS property files identified by the OHS administrator.

After applying the changes, restart the Oracle HTTP Server services.

Expected Result

After the restart:

• The host becomes visible in Dynatrace.
• Oracle HTTP Server (ohs* / httpd.worker) is detected.
• Deep Monitoring is enabled.
• Services and traces generated by OHS become available in Dynatrace.

What's next

If this article did not resolve the issue, please open a Dynatrace Support ticket and mention that this article was followed during troubleshooting.

Please include the following information in the ticket:

• Link(s) to the documentation used during the configuration
• Screenshot(s) of the OHS property file configuration showing the added environment variables
• Output of: pargs -e <httpd_worker_pid>