The OpenTelemetry Spring Boot starter provides out of the box instrumentation that you can augment with additional instrumentations.

You have to add the OpenTelemetry appender to your log4j2.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" packages="io.opentelemetry.instrumentation.log4j.appender.v2_17">
    <Appenders>
        <OpenTelemetry name="OpenTelemetryAppender"/>
    </Appenders>
    <Loggers>
        <Root>
            <AppenderRef ref="OpenTelemetryAppender" level="All"/>
        </Root>
    </Loggers>
</Configuration>

You can find more configuration options for the OpenTelemetry appender in the Log4j instrumentation library.

{{< tabpane text=true >}} {{% tab "Properties" %}}

Enables the configuration of the Log4j OpenTelemetry appender with an OpenTelemetry instance:

otel:
  instrumentation:
    log4j-appender:
      enabled: true # default: true

{{% /tab %}} {{% tab "Declarative Configuration" %}}

In declarative configuration, use the centralized instrumentation lists to enable or disable Log4j:

otel:
  distribution:
    spring_starter:
      instrumentation:
        disabled:
          - log4j_appender

{{% /tab %}} {{< /tabpane >}}

You can configure other instrumentations using OpenTelemetry instrumentation libraries.