OpenStack Eventlet Removal Resources
OpenStack has embarked on a significant technical initiative to remove Eventlet dependencies across all its components. This section provides resources, updates, and insights into this community-wide effort.
Why is OpenStack Removing Eventlet?
The OpenStack Technical Committee (TC) has established Eventlet removal as a top priority for several key reasons:
Python Evolution
Eventlet faces significant compatibility issues with all recent Python versions starting from Python 3.12. These challenges are further exacerbated by Python 3.13 and the PEP 703 "GILectomy" implementation, making migration critical for ensuring future compatibility.
Maintenance Challenges
Diminishing maintenance activity in the Eventlet project means bugs accumulate faster than they're fixed, creating reliability issues.
Compatibility Problems
Integration issues between Eventlet and important libraries like RabbitMQ cause persistent operational problems in OpenStack deployments.
Performance Optimization
Benchmarks have shown performance advantages with alternative concurrency implementations compared to Eventlet's approach.
OpenStack PTG Updates
The OpenStack Project Teams Gathering (PTG) events have featured significant discussions about Eventlet removal. Explore the documentation from these sessions to understand the community's approach and progress.
- Hibiscus PTG (April 2026): Gazpacho Retrospective & Hibiscus Call to Action
- Flamingo PTG (April 2025): Eventlet Discussions
Updates from future PTGs will be added here
Project-Specific Resources
Different OpenStack projects have adopted various approaches to Eventlet removal. Below are examples and resources from specific components.
- Octavia: A Complete Migration Case Study
- Neutron: Eventlet Removal Patches
- Oslo.service: New Threading Backend
- Nova: Eventlet Removal Progress Tracking
- Nova: Balazs Gibizer's Blog on Eventlet Migration - Detailed articles tracking Nova's progress
Additional project resources will be added as they become available
Current Migration Status Summary 🔗
The progress of Eventlet removal varies across OpenStack projects. Here's a high-level overview as of April 2026 (Hibiscus cycle):
| Project | Status | Approach |
|---|---|---|
| Octavia | Completed | Migration completed since 2017 Show the migration history |
| Mistral | Completed | Migration completed since September 2025. Show the migration history |
| Ironic | Completed | Migration completed since August 2025. Show the migration history |
| Barbican | Completed | Migration completed since August 2025. Show the migration history |
| Heat | Completed | Migration completed since July 2025. Show the migration history |
| Cyborg | Completed | Eventlet-free since Gazpacho. Removed monkey patch, fixed DB deadlock, native WSGI server removed Show the migration history |
| Neutron | Completed | Migration completed in Gazpacho. Moved Oslo services to threading mode, removed all eventlet imports Show the migration history |
| Designate | Completed | Migration completed in Gazpacho. Full migration finished, major milestone achieved Show the migration history |
| Oslo Libraries | In Progress | Multiprocessing spawn support introduced, deprecated Eventlet features, oslo.db supports asyncio, oslo.service's threading backend implemented. Working on making eventlet dependencies optional Show the migration history |
| Glance | In Progress | Good shape. Removed eventlet from utils, unit tests use native threading. Client migration pending Show the migration history |
| Nova | In Progress | Service-by-service approach. Gazpacho: API, metadata, scheduler default to threading. Hibiscus: compute and conductor default to threading. Pending: console proxies Show the migration history |
| Cinder | In Progress | Volume and scheduler services operational with threading, aligned with recent Oslo services. Backup service in progress Show the migration history |
| Manila | In Progress | Advanced progress. Share manager migrated, Rally performance framework developed showing no significant regression. Planning functional tests for Hibiscus Show the migration history |
| Watcher | In Progress | All components migrated (API, Decision Engine, Applier). Switched to threading by default in early Hibiscus Show the migration history |
| Swift | In Progress | 100% functional tests passing, 99% unit tests passing. Working on erasure coding predictability challenges Show the migration history |
| Blazar | In Progress | Evaluating alternatives to Eventlet WSGI, gradual transition approach Show the migration history |