Following the intensive discussions at the April 2025 Project Teams Gathering about the Eventlet removal initiative, this thread summarizes the current status, challenges, and strategies of all the OpenStack teams with a transversal perspective. A full and detailed report is available at: https://removal.eventlet.org/guide/openstack/flamingo-ptg/ ## Python 3.13 Compatibility The countdown has begun! As documented in the April 2025 PTG discussions, the OpenStack community is accelerating efforts to remove Eventlet dependencies across all projects. This initiative has become critical due to Eventlet's compatibility problems with Python 3.13 and the upcoming "GILectomy" (PEP 703). With Ubuntu 2025.4 planning to ship Python 3.13 by default, we're facing a hard deadline for this work https://discourse.ubuntu.com/t/plucky-puffin-release-schedule/36461 ## Migration Status ### Significant Progress - Octavia: Fully migrated since 2017! Their approach is now documented as a community case study. - Mistral: Almost there with a comprehensive migration approach. - Neutron: Significant progress with numerous patches already merged. - Glance: Can be deployed without Eventlet, though some optional features still need work. ### Work in Progress - Nova: Planning a service-by-service migration with dual-mode support during transition. - Swift: Evaluating alternatives with impressive performance results (FastWsgi showing 10x better performance!). - Manila, Cinder, Heat: All have active plans for the Flamingo cycle. - Designate, Blazar, Watcher: Starting their migration journeys. - Ironic: Facing complex challenges, particularly with the Ironic Python Agent component. ## Technical Spotlight: Oslo.service's Threading Backend A key development is the new threading backend for oslo.service that eliminates the Eventlet dependency: - Review in progress: https://review.opendev.org/c/openstack/oslo.service/+/945720 - No longer provides WSGI support - Each service will need to deprecate implementations dependent on Eventlet's WSGI server ## Migration Strategies: One Size Doesn't Fit All Projects are adopting diverse approaches: - Dual-mode support: Nova and Glance are supporting both Eventlet and native threads during transition - Canary approach: Swift is considering starting with proxy nodes - Component-by-component: Cinder is starting with the Volume Manager - Complete replacement: Heat is planning a full discontinuation of WSGI server implementations ## Nova's Detailed Roadmap Nova has a comprehensive two-cycle plan: Flamingo Cycle (2025.2): - API modernization - Architecture updates with environment variable controls - Performance improvements - Test transition to native threading Guppy Cycle (2026.1): - Core event loop conversion - Adoption of oslo.service's new threading backend ## Issues to Watch: RabbitMQ Heartbeat Problems The problem with RabbitMQ heartbeats story: - Timeouts and API failures in "green" environments - Partial solution using pthreads exists but has logging issues - Track the fix: https://review.opendev.org/c/openstack/oslo.log/+/937729 ## How to Get Involved - Join the #openstack-eventlet-removal channel on OFTC - Review the official guide: https://removal.eventlet.org/ - Look for patches under the "eventlet-removal" topic: https://review.opendev.org/q/prefixtopic:%22eventlet-removal%22 ## Recommended Reading For teams starting their migration: 1. Official goal documentation: https://governance.openstack.org/tc/goals/selected/remove-eventlet.html 2. Migration preparation guide: https://removal.eventlet.org/guide/preparing-for-migration/ 3. Octavia case study: https://removal.eventlet.org/guide/case-studies/octavia/ ## Stay Updated - The complete version of this report is available online at: https://removal.eventlet.org/guide/openstack/flamingo-ptg/ - Track the progress of the migration across all projects at: https://removal.eventlet.org/guide/openstack/#migration-status Thanks for reading! PS: This PTG summary is based on the etherpads following the April 2025 PTG discussions (https://ptg.opendev.org/etherpads.html). For more details, refer to the full report ( https://removal.eventlet.org/guide/openstack/flamingo-ptg/).