Python supported components and versions

Thread starting permission

The Instana Python tracer needs permission to create and start Python threading.Timer objects. On most systems, this permission is granted by default. In some nested containerization scenarios, for example in some "Docker in Docker" container versions, the permission is not granted by default.

If you see exceptions like RuntimeError: can't start new thread, then insufficient permissions are the most likely cause. If you upgrade or change the "Docker in Docker" container, but the needed permissions are not granted for the internal application container, then you can use the --privileged permission as a last resort to start the application container.

Tracing across thread boundaries

The Instana Python package does not support tracing across thread boundaries. For example, when a request is first handled on a single thread, and then the workload is distributed to multiple other threads with the help of multiprocessing.ThreadPool, outgoing calls that happen in those other threads are not captured. Because every exit span needs to have an entry span, and the initiating entry span is out of the thread scope, such outgoing calls are not recorded. This is caused by the inherent characteristic of the default OpenTracing ThreadLocalScopeManager, and the lack of a ThreadPool specific scope manager.

Tracing with multiple tracers

It is not supported to trace a single Python application with Instana and a third-party tracer, for example, with New Relic tracer or OpenTelemetry at the same time.