Middleware.io: no data in APM means the agent is not attached or cannot reach it

TL;DR

Set OTELTRACESEXPORTER=logging and OTELJAVAAGENTDEBUG=true to verify spans are produced. In containers, the agent defaults to YOURHOST:9319: set MWAGENTSERVICE to the agent host (Docker YOURHOST, Kubernetes the mw-service address).

Steps

1. [Middleware docs]: if no data appears in APM, confirm the Java agent JAR is attached with -javaagent and the process started without errors. Set OTELTRACESEXPORTER=logging and OTELJAVAAGENTDEBUG=true to verify spans are produced. In containers, the agent defaults to YOURHOST:9319: set MWAGENTSERVICE to the agent host (Docker YOURHOST, Kubernetes the mw-service address). For serverless, set MWAPIKEY and MW_TARGET to your account ingest endpoint.

When to use

You are seeing this: [Middleware docs]: if no data appears in APM, confirm the Java agent JAR is attached with -javaagent and the process started without errors. Use this skill when you run into "Middleware.io: no data in APM means the agent is not attached or cannot reach it".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: No traces usually means attachment or connectivity, not a UI problem.

Verified resolution: [Middleware docs]: if no data appears in APM, confirm the Java agent JAR is attached with -javaagent and the process started without errors. Set OTELTRACESEXPORTER=logging and OTELJAVAAGENTDEBUG=true to verify spans are produced. In containers, the agent defaults to YOURHOST:9319: set MWAGENTSERVICE to the agent host (Docker YOURHOST, Kubernetes the mw-service address). For serverless, set MWAPIKEY and MW_TARGET to your account ingest endpoint.

Source URL: https://docs.middleware.io/apm-configuration/java