8705f67bfb
We initially started to work on this topic with the intention to solve
the problem of using the Eventlet hub_prevent_multiple_readers debug feature.
This feature is a debug convenience. This feature is not supported by the new
asyncio hub[1] of Eventlet. You can also check the documentation here[2] from eventlet. The problem with disabling this procedure is that
it exposes you to risk. Deactivation applies to the entire stack. If a project
uses oslo.log, for example nova, then it exposes all threads to concurrent access
on the process file descriptors.
As explained in the function's documentation[3], when several greenlets are reading from
the same socket, it's difficult to predict which greenlet will receive which data.
You really need to be sure of what you're doing to use this function. Also explained
in the raise condition added by this commit[4] and we have a reproducer[5] that exposes
the problem. According to our tests, removing this line does not change the fix provided.
It also seems that cinder no longer uses[6] logging native thread.
Related-Bug: #1983863
[1] https://review.opendev.org/c/openstack/governance/+/902585/17..18
[2] https://eventlet.readthedocs.io/en/latest/asyncio/migration.html#known-limitations-and-work-in-progress
[3] https://github.com/eventlet/eventlet/blob/master/eventlet/debug.py#L149
[4] cb7c8c0196
[5] https://github.com/4383/oslo.log/blob/reproducer2/reproducer.py
[6] https://bugs.launchpad.net/oslo.log/+bug/1983863/comments/18
Co-authored-by: Hervé Beraud <hberaud@redhat.com>
Change-Id: Ia4c8e82f957c4ef3c176246fea0bc0adab4f4dc4
Team and repository tags
oslo.log -- Oslo Logging Library
The oslo.log (logging) configuration library provides standardized configuration for all openstack projects. It also provides custom formatters, handlers and support for context specific logging (like resource id's etc).
- Free software: Apache license
- Documentation: https://docs.openstack.org/oslo.log/latest/
- Source: https://opendev.org/openstack/oslo.log
- Bugs: https://bugs.launchpad.net/oslo.log
- Release notes: https://docs.openstack.org/releasenotes/oslo.log/