External Task Runner v2.4.8: error when launching runner process

Questions
3

Thanks a lot for your previews response, but it doesn’t work.
I made some edits to files but… ( I wrote \ because the response here I can’t put links so it doesn’t recognize with ), and sorry for my english.

Problem running external task runners (v2.6.3): launcher keeps requesting Python runner even with JavaScript-only config

I’m trying to set up external task runners with n8n 2.6.3 and the n8nio/runners:2.6.3 image, extended to add Puppeteer and related packages for JavaScript Code nodes.

The goal is:

  • n8n 2.6.3 as the main instance (broker)

  • a single external runners container (JavaScript only, no Python)

  • custom n8n-task-runners.json that allowlists Puppeteer packages

However, the runners container keeps crashing with this error:

ERROR Failed to load config: config file at /etc/n8n-task-runners.json does not contain requested runner type: python

Even though my config only defines a JavaScript runner.

Current setup

n8n service (docker-compose)

`n8n:
image: \docker.n8n.io/n8nio/n8n:2.6.3
restart: always
environment:
- DB_TYPE=postgresdb
- DB_POSTGRESDB_HOST=postgres
- DB_POSTGRESDB_PORT=5432
- DB_POSTGRESDB_DATABASE=${POSTGRES_DB}
- DB_POSTGRESDB_USER=${POSTGRES_NON_ROOT_USER}
- DB_POSTGRESDB_PASSWORD=${POSTGRES_NON_ROOT_PASSWORD}
- N8N_HOST=${N8N_DOMAIN}
- N8N_PORT=5678
- N8N_PROTOCOL=https
- N8N_SECURE_COOKIE=true
- N8N_BASIC_AUTH_ACTIVE=${N8N_BASIC_AUTH_ACTIVE}
- N8N_BASIC_AUTH_USER=${N8N_BASIC_AUTH_USER}
- N8N_BASIC_AUTH_PASSWORD=${N8N_BASIC_AUTH_PASSWORD}
- WEBHOOK_URL=\https://${N8N_DOMAIN}/
- GENERIC_TIMEZONE=${GENERIC_TIMEZONE}
- TZ=${TZ}
- NODE_ENV=production
- N8N_ENCRYPTION_KEY=${N8N_ENCRYPTION_KEY}

# Task runners (external mode)
- N8N_RUNNERS_ENABLED=true
- N8N_RUNNERS_MODE=external
- N8N_RUNNERS_BROKER_LISTEN_ADDRESS=0.0.0.0
- N8N_RUNNERS_AUTH_TOKEN=${N8N_RUNNERS_AUTH_TOKEN}

volumes:
- n8n_storage:/home/node/.n8n
depends_on:
postgres:
condition: service_healthy
mongodb:
condition: service_healthy
networks:
- n8n-network
expose:
- 5678`

task-runners service (docker-compose)

task-runners: build: context: . dockerfile: Dockerfile.runners container_name: n8n-runners environment: - N8N_RUNNERS_TASK_BROKER_URI=http://n8n:5679 - N8N_RUNNERS_AUTH_TOKEN=${N8N_RUNNERS_AUTH_TOKEN} - N8N_RUNNERS_LAUNCHER_HEALTH_CHECK_PORT=5680 - N8N_RUNNERS_RUNNER_TYPE=javascript volumes: - ./n8n-task-runners.json:/etc/n8n-task-runners.json depends_on: - n8n

So:

  • N8N_RUNNERS_TASK_BROKER_URI uses http:// and points to the n8n service on port 5679, as per the docs for external mode.

  • The same N8N_RUNNERS_AUTH_TOKEN is used in both n8n and task-runners. [Task runners external; Task runner env vars]

Dockerfile for runners

`FROM n8nio/runners:2.6.3

USER root

JS runner: install Puppeteer and related packages

RUN cd /opt/runners/task-runner-javascript &&
pnpm add puppeteer-extra puppeteer puppeteer-core @\ghostery/adblocker-puppeteer

Custom config for runners

COPY n8n-task-runners.json /etc/n8n-task-runners.json

USER runner`

This follows the pattern from the docs for extending n8nio/runners and adding extra dependencies. [Adding extra deps]

n8n-task-runners.json

{ "task-runners": [ { "runner-type": "javascript", "env-overrides": { "NODE_FUNCTION_ALLOW_BUILTIN": "*", "NODE_FUNCTION_ALLOW_EXTERNAL": "puppeteer-extra,puppeteer,puppeteer-core,@ghostery/adblocker-puppeteer", "N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION": "true" } } ] }

So there is only a JavaScript runner defined, no Python runner at all.

What I already tried

  • Initially I had both JavaScript and Python runners defined in n8n-task-runners.json.
    The launcher then complained about:

runner python: health-check-server-port is required with multiple runners

  • Since I only need JavaScript, I removed the Python block from n8n-task-runners.json, leaving only the JavaScript runner (as shown above).

  • After that, the error changed to:

ERROR Failed to load config: config file at /etc/n8n-task-runners.json does not contain requested runner type: python

  • Based on a community thread, I added N8N_RUNNERS_RUNNER_TYPE=javascript to the task-runners service, to explicitly tell the launcher to use the JavaScript runner type. [Runner type thread]

  • I rebuilt and restarted everything with:

docker compose down docker compose up -d --build

  • Despite this, the n8n-runners container still exits immediately, and docker compose logs -f task-runners always shows:

ERROR Failed to load config: config file at /etc/n8n-task-runners.json does not contain requested runner type: python

  • Because the container exits right away, I can’t easily docker exec into it to inspect environment variables, but the compose file clearly sets N8N_RUNNERS_RUNNER_TYPE=javascript.

What I’m asking for

I would really appreciate help understanding:

  1. Why the launcher in n8nio/runners:2.6.3 is still requesting a python runner type, even though:

  • N8N_RUNNERS_RUNNER_TYPE=javascript is set on the runners container, and

  • n8n-task-runners.json only defines a runner-type: "javascript".

  1. Whether there is:

  • a different or updated way to configure “JavaScript-only” runners in v2.6.3,

  • or any additional environment variables or flags that must be set to avoid the launcher defaulting to python.

  1. If this might be a bug or regression in the task-runner launcher for v2.6.3, and if there is a recommended workaround.

My main goal is simply to have:

  • n8n 2.6.3 in external runners mode,

  • a single runners container with JavaScript only,

  • Puppeteer and related packages available in the Code node via the external runners.

Thank you very much in advance for any guidance or examples you can share.