Auto workers scaling

Beta notice

This feature is still in beta, errors are expected. Do not use it in production environments.

Introduction

This feature became available starting with the RoadRunner 2024.3 release. Users can now scale their RoadRunner workers automatically, up to an additional 100 workers.

Supported plugins

• All plugins that support a worker pool are supported.

Limitations

• This feature is unavailable when running RoadRunner in debug mode (*.pool.debug=true).

• This feature does not scale Temporal workflow workers; only activity workers are scaled.

How it works

RoadRunner uses the pool.allocate_timeout option to determine when to start spawning additional workers. If no workers are available to handle the request before the timeout expires, RoadRunner begins dynamically allocating additional workers according to the spawn_rate.

Usage

Below is a configuration example demonstrating how to use this new feature:

.rr.yaml

version: '3'

rpc:
  listen: tcp://127.0.0.1:6002

server:
  command: "php worker.php"

http:
  address: 127.0.0.1:10085
  pool:
    num_workers: 2
    allocate_timeout: 60s
    destroy_timeout: 1s
    dynamic_allocator:
        max_workers: 25
        spawn_rate: 10
        idle_timeout: 10s

logs:
  mode: development
  level: debug

Configuration

The new dynamic_allocator section has been added to the *.pool configuration. It contains the following parameters:

• max_workers - the maximum number of workers that can be additionally spawned.

• spawn_rate - the number of workers that can be spawned per NoFreeWorkers error (but up to max_workers).

• idle_timeout - the time after which dynamically allocated workers are considered not needed and will be deallocated.