Enable Selective Monitoring Support for Instana for Z (z/OS)

Instana for Z currently does not support Selective Monitoring using environment variables, causing excessive discovery and preventing targeted JVM monitoring on z/OS. Requesting an alternative mechanism (JVM args, config files, etc.) and documentation updates.

Based on IBM Support case TS021631271, we discovered that Selective Monitoring does not function as documented when using the Instana agent on z/OS.

The documented approach for Selective Monitoring requires setting:

INSTANA_MONITORING=TRUE

However, for WebSphere Application Server (WAS) on z/OS, environment variables are transformed internally (e.g., converting "true" to "1"). The Instana for Z agent does not recognize "1" as a valid enabling value. As a result:

• Selective Monitoring does not activate.
• The Z agent performs unnecessary process discovery, creating noise and overhead.
• Customers cannot target specific WAS JVMs for monitoring.

Per IBM Support:

“This won’t work on Z as we don’t have the env vars for processes on z/OS before we are able to attach. This functionality is not available today.”

Additionally, the public documentation does not indicate that environment-variable–based Selective Monitoring is unsupported for Instana for Z.

Ideally a proposed solution is to treat "1" as equivalent to "true" for compatibility.

Additionally, consider to Update documentation to clearly state current limitations for Instana for Z.
https://www.ibm.com/docs/en/instana-observability/1.0.315?topic=agents-instana-selective-monitoring