Migrating from Fly.io

Fly.io runs Docker images as Machines in many regions. Fjordrun runs containers in one region (Nuremberg, Germany) and builds them for you from your repository. Most Fly apps move over without code changes.

Concept map

Fly.io	Fjordrun
App	Service (in a project)
Separate apps for staging and production	Environments in one project
fly.toml	Service settings in the dashboard (start command, port, healthcheck, replicas, resources)
Dockerfile, or fly launch scanners	Fjordrun builder: a repository Dockerfile always wins; otherwise Node.js framework detection, or Nixpacks for other languages
[http_service] internal_port	Port of the service (default 8080)
[[http_service.checks]]	Healthcheck path
[processes] groups	One service per process from the same repository (a web service and worker services)
release_command	Prefix the start command, for example npx prisma migrate deploy && node server.js
[[vm]] size	vCPU and memory limits per replica; billed on actual use
auto_stop_machines / min_machines_running = 0	Sleep when idle
Machine count	Replicas
fly secrets	Service variables
Fly Volumes	Volumes (one per service)
<app>.internal private networking	<service>.<environment>.internal (Private networking)
Fly Postgres / Upstash Redis	PostgreSQL / Redis templates
*.fly.dev	*.fjordrun.app generated domains
flyctl	fjordrun CLI
Multiple regions	One region during the beta: nbg1 (Regions)

Steps

1. Create a project on Fjordrun and add a service from your GitHub repository. If the repository has a Dockerfile (most Fly apps do), Fjordrun builds it as it is.
2. Port: set Settings → Deploy → Port to the internal_port from fly.toml, or make the app listen on $PORT.
3. Healthcheck: copy the path of your HTTP check into Healthcheck path.
4. Other processes: for each extra entry under [processes], add a service from the same repository with kind worker and that command as its start command.
5. Secrets: Fly does not show secret values again, so copy them from where you keep them (your password manager or .env files) into the raw variables editor as KEY=value lines. Replace hostnames that end in .internal with references to the new services, for example DATABASE_URL=${{Postgres.DATABASE_URL}}.
6. Volumes and databases: attach a volume at the same mount path, create databases from templates, and move the data (below).
7. Deploy, test on the generated *.fjordrun.app domain, then move your custom domain.

Images you build yourself must include linux/arm64: during the beta Fjordrun's servers are arm64 machines. See Docker. Images that Fjordrun builds from your repository need no change.

PostgreSQL

Open a tunnel to the Fly database and dump it from your machine:

fly proxy 15432:5432 -a <postgres-app>
# in a second terminal
pg_dump "postgresql://postgres:<password>@localhost:15432/<database>" \
  --format=custom --no-owner --no-acl --file=fly.dump

Fjordrun databases are private, so restore from a container inside the project, as described in Railway → Databases.

Stop writes to the old database (for example scale the app to zero with fly scale count 0) before the final dump.

Files on Fly Volumes

Copy files out with fly ssh sftp get (or create a tar archive in the Machine with fly ssh console and download it), then upload them to the Fjordrun service's volume from a temporary container in the same way as a database dump.

Domains

Add the custom domain in Fjordrun and create the TXT verification record. When the new deployment works, replace the Fly A/AAAA (or CNAME) records with a CNAME to edge.fjordrun.app, and remove the certificate on Fly (fly certs remove). See Domains and HTTPS.

Pricing differences

Fly bills Machines by size and running time. Fjordrun bills the CPU and memory a service actually uses: €12 per vCPU-month and €6 per GB-month (excl. VAT), with plans from €0 (Trial), €5 (Hobby) and €20 (Pro) that include the same amount of usage. See Usage-based pricing.