When to use Modal
Use Modal when:- several people may run tasks at the same time
- task work should not consume CPU or memory on the Roomote host
- you want hosted sandboxes with snapshot support
- you can provide Modal credentials and a worker image Modal can pull
Configuration
Add Modal from Settings > Compute, or provide the values as deployment env vars:MODAL_BASE_IMAGE_REF
from the shared worker image configured in Settings > Compute or
DOCKER_WORKER_IMAGE:
MODAL_BASE_IMAGE_REF only when you need to pin a custom Modal base image:
Worker image expectations
Hosted providers cannot use a local-only image tag such asroomote-worker:local. The worker image must be registry-qualified and
reachable by Modal. If Modal cannot pull the image, tasks will fail before the
worker runtime starts.
Verify setup
- save Modal credentials and a registry-qualified worker image
- select Modal as the default compute provider
- start a small task from an environment
- confirm the task starts, streams logs, and can run project commands
- try resuming or following up on a task that can use a saved snapshot
Common issues
- Modal cannot pull the worker image. Use a registry-qualified image and configure registry credentials or ECR OIDC settings when needed.
- Tasks fail immediately after launch. Check
MODAL_TOKEN_ID,MODAL_TOKEN_SECRET, and any Modal environment or endpoint overrides. - The wrong worker runtime starts. Pin
DOCKER_WORKER_IMAGEorMODAL_BASE_IMAGE_REFto an immutable tag.