Docker

Flynn supports deploying Docker images directly, without requiring a buildpack build step.

Deploying a Docker Image

# Create the app
flynn create my-app

# Push a Docker image
flynn docker push my-registry.com/my-image:latest

Flynn pulls the image, creates a release, and deploys it.

Push a locally-built image:

docker build -t my-app .
flynn docker push my-app

Flynn routes HTTP traffic to the port specified by the PORT environment variable (default: 8080). Your application should listen on $PORT:

ENV PORT 8080
EXPOSE 8080
CMD ["./server", "--port", "8080"]

Or read the PORT env var dynamically:

const port = process.env.PORT || 8080;
app.listen(port);

Define multiple process types using the CMD and labels, or specify them after push:

flynn scale web=2 worker=1

Set configuration the same way as buildpack apps:

flynn env set DATABASE_URL=postgres://...

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install --production
COPY . .
ENV PORT 8080
EXPOSE 8080
CMD ["node", "server.js"]

docker build -t my-node-app .
flynn create my-node-app
flynn docker push my-node-app