Best Practices for Windmill on AWS ECS Fargate with Autoscaling Workers
Setup:
- AWS ECS Fargate, 3-15 autoscaling workers
- EFS at /tmp/windmill/logs, ephemeral /tmp/cacheworker for pip cache
- Version: ghcr.io/windmill-labs/windmill:main
Issue:
Intermittent ModuleNotFoundError: No module named 'shopify.resources.option' when
workers scale.
Current Config:
worker_groups = [{
cpu = 2048, memory = 4096
min_capacity = 3, max_capacity = 15
environment = { CACHE_DIR = "/tmp/cacheworker" } # Ephemeral
}]
Questions:
1. Recommended cache strategy for Fargate?
- Ephemeral /tmp vs EFS for pip cache?
- Does Windmill have locking for concurrent pip installs?
2. Can we pre-bake packages into custom worker images?
- Install all packages from .script.lock at image build time?
- Will this conflict with Windmill's package management?
3. ECS/Fargate reference architecture?
- Any documented patterns for dynamic scaling?
- Warm pool or pre-installation strategies?
4. What do production users do?
- Custom images vs shared cache vs per-worker install?
Considering: Building custom image with pre-installed packages for 5-10s startup vs
current 60-90s.
- AWS ECS Fargate, 3-15 autoscaling workers
- EFS at /tmp/windmill/logs, ephemeral /tmp/cacheworker for pip cache
- Version: ghcr.io/windmill-labs/windmill:main
Issue:
Intermittent ModuleNotFoundError: No module named 'shopify.resources.option' when
workers scale.
Current Config:
worker_groups = [{
cpu = 2048, memory = 4096
min_capacity = 3, max_capacity = 15
environment = { CACHE_DIR = "/tmp/cacheworker" } # Ephemeral
}]
Questions:
1. Recommended cache strategy for Fargate?
- Ephemeral /tmp vs EFS for pip cache?
- Does Windmill have locking for concurrent pip installs?
2. Can we pre-bake packages into custom worker images?
- Install all packages from .script.lock at image build time?
- Will this conflict with Windmill's package management?
3. ECS/Fargate reference architecture?
- Any documented patterns for dynamic scaling?
- Warm pool or pre-installation strategies?
4. What do production users do?
- Custom images vs shared cache vs per-worker install?
Considering: Building custom image with pre-installed packages for 5-10s startup vs
current 60-90s.
