TL;DR: We just recently passed Flamingo's milestone 3 and since the last ML update we observed tremendous progress. Ironic, Barbican, Heat completed their migration. Futurist has been improved with new useful features for threading mode. The migration timeline has been adjusted to match Nova's dual mode support. PTG is under preparation. Statistics show good progress. Eventlet now supports Python 3.14.

## OpenStack Updates

From a statistical perspective:
- almost 17% of the occurences of the runtime code initially impacted by Eventlet have been tackled — outside of code dedicated to test, doc, releasenotes, etc;
- if we include all the spectrum of occurrences to migrate — code, tests, doc, examples — it represent ~14% of the entire code base already migrated;
- more than 40% of all impacted repositories have made some progress in link with the migration;
- 13 projects have been fully migrated since the beginning;
- more than 332 patches related to the eventlet migration have been submitted to gerrit.

From the teams perspective, we can highlight
Ironic completed its migration, for the occasion wrote an excellent write-up [1] — thanks Julia — I strongly encourage you to read it.
Barbican [2] and heat [3] successfully completed their migrations too. They are now fully threading based.

Dmitry in collaboration with the Ironic team implemented a DynamicPoolExecutor in Futurist [4]. It helps replace dynamic GreenPool.

Oslo.service's backend system is now documented [5].

There is still ongoing work on several OpenStack deliverables: Neutron, Nova, Manila, Magnum, Mistral, Watcher, Designate, Trove, etc. All these teams demonstrated awesome progress.

The migration timeline has been adjusted at the governance level to match Nova's dual mode support [6].

There is ongoing preparation of the PTG sessions. I think there will be a short slot during one of the TC sessions, and surely a fully dedicated one hour slot to host cross team open discussions.

## Eventlet Updates

The support of Python 3.14 has been introduced within Eventlet 0.40.2.

A vulnerability (CVE-2025-58068, CVSS 6.3) in Eventlet’s WSGI parser allowing HTTP Request Smuggling (bypass controls, cache poisoning, user targeting) has been found. It has been fixed within Eventlet 0.40.3. A security advisory has been published [7].

## Call to Action

That would be worth considering introducing small experiments as opportunities to identify or learn any weaknesses in new threading architectural models. That could start by preparing and performing some perf scale testing at your deliverables levels. That will help you to define the right scaling configuration for your deliverables. You can draw inspiration from Neutron's rally jobs [8] and from Ironic's scripting created for benchmark purposes [9]. More than a year ago, Dan sparked the performance testing topic idea [10], that's the right time to consider it more deeply.

If you do not start the migration of your deliverables, I'd encourage you to plan and prioritize it as soon as possible. Time flies and the later your migration starts the harder it will be. Python 3.15 comes with its share of breaking changes [11] so I'd not suggest waiting for that time.

If you are scheduling a PTG session on your side about Eventlet, then please let us know by updating the eventlet removal wiki page [12].

If your service is now migrated, I'd invite you to tag the launchpad bugs which were related to Eventlet, and, if it makes sense to close them. You are now entering a clean phase.

## Final Thoughts

During Flamingo we observed tremendous progress, and we are now going straight toward the final release of Flamingo.
The PTG, and Gazpacho that will be the logical continuation of the jobs already done.
Flamingo will mark a significant release due to the fully migrated bricks and services. They will allow us to enter a beneficial feedback loop.

The migration path is now well cleared by all the previous actions and changes applied into OpenStack.
Postponing the beginning of the migration will make your life harder. We want to prevent this from happening to you.
Your journey start here https://removal.eventlet.org/

If you need information join-us on the #openstack-eventlet-removal OFTC channel.

Thanks to all the people who made this migration possible until now.

Thanks for your attention.

[1] https://ironicbaremetal.org/blog/coming-soon-threading/
[2] https://review.opendev.org/c/openstack/barbican/+/955301
[3] https://review.opendev.org/c/openstack/heat/+/952651
[4] https://docs.openstack.org/futurist/latest/reference/index.html#futurist.DynamicThreadPoolExecutor
[5] https://docs.openstack.org/oslo.service/latest/user/backend.html
[6] https://review.opendev.org/c/openstack/governance/+/952903
[7] https://github.com/advisories/GHSA-hw6f-rjfj-j7j7
[8] https://opendev.org/openstack/neutron/src/branch/master/rally-jobs
[9] https://opendev.org/openstack/ironic/src/branch/master/tools/benchmark
[10] https://review.opendev.org/c/openstack/governance/+/902585/comment/979db3f6_275b001a/
[11] https://docs.python.org/es/dev/whatsnew/3.15.html#threading
[12] https://wiki.openstack.org/wiki/Eventlet-removal#Project-specific_events

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Hervé Beraud
Principal Software Engineer at Red Hat
irc: hberaud