Gunicorn 25.1: Control Interface

Gunicorn 25.1, released in February 2025, adds a control interface enabling dynamic worker scaling. The worker count can be adjusted at runtime without restart, improving production load management.

Dynamic Scaling

bash 
# Start with control interface
gunicorn myapp:app --workers 4 --bind 0.0.0.0:8000

# Increase workers at runtime
# kill -TTIN $(cat gunicorn.pid)   # +1 worker
# kill -TTOU $(cat gunicorn.pid)   # -1 worker

# Graceful reload
# kill -HUP $(cat gunicorn.pid)

Sources