# Migrate Netlify web app: Rails

## Summary

Move Rails compute from Netlify web app to Ample, one component at a time. Destination verified on Ample: the app built, started and answered on its public HTTPS URL with encrypted configuration delivered. Source procedure: Copy environment variables from Site configuration (or `netlify env:list`) into an env file kept out of the repository. Not migrated automatically: Netlify Functions, Edge Functions, Forms, Identity and `_redirects`/`_headers` rules are not migrated; implement redirects in the app or the framework. Cutover: Add the custom domain with `ample domain add`, set the documented DNS records, keep the Netlify site until verified, then remove the domain from Netlify. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## Infrastructure requirements

- [Compute](/content/discover/primitive/compute/index.html): verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- [Postgres](/content/discover/primitive/postgres/index.html): verified (Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.)

## Prerequisites

- Authorized access to the Netlify web app source and its export tooling
- An inventory of every component in scope and out of scope
- A validated backup or copy before any cutover
- An Ample account token with servers:write, databases:read

## Exact tested configuration

- template: `ruby-3.4`
- runtime: `ruby`
- size: `s-1vcpu-1gb`
- install: `bundle config set --local path vendor/bundle && bundle config set --local without 'development test' && bundle install`
- start: `bundle exec rails server -b 0.0.0.0 -p $PORT`

## Steps

1. **Inventory the source.** List what Netlify web app provides beyond the component you are moving. Out of scope here: Netlify Functions, Edge Functions, Forms, Identity and `_redirects`/`_headers` rules are not migrated; implement redirects in the app or the framework.
2. **Source step 1.** Copy environment variables from Site configuration (or `netlify env:list`) into an env file kept out of the repository.
3. **Source step 2.** Translate `netlify.toml` build settings (command, publish directory) into the repository's own build script; Ample runs the detected build.
4. **Source step 3.** List Netlify-only features in use: functions, edge functions, forms, identity, redirects and headers rules.
5. **Deploy on Ample in parallel.** bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via `rails server` reading PORT on the ruby-3.4 template with RAILS_ENV=production. Pass the exported variables with --env;
   
   ```
   ample deploy . --name <app-name> --public --env-file .env.production
   ```
6. **Validate before cutover.** Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/configuration-secrets, /p/relational-records).
7. **Cut over.** Add the custom domain with `ample domain add`, set the documented DNS records, keep the Netlify site until verified, then remove the domain from Netlify.
8. **Rollback.** Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Tested examples

- **Rails pattern fixture (destination)** (tests/deploy-canaries/rails-patterns): Verified destination basis: Rails compute.

## Success checks

- destination app responds on its public URL (`/` on the live URL, expect ample canary rails patterns)
- configuration-secrets check from the destination example (`/p/configuration-secrets` on the live URL, expect see the pattern fixture checks)
- relational-records check from the destination example (`/p/relational-records` on the live URL, expect see the pattern fixture checks)
- data or object counts and checksums match the source

## Limitations

- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from Netlify web app's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
- No full source-product parity is claimed: Netlify Functions, Edge Functions, Forms, Identity and `_redirects`/`_headers` rules are not migrated; implement redirects in the app or the framework.
- Verified on the ruby-3.4 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures on the managed side are not verified beyond the pattern checks.

## Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1 `s-1vcpu-1gb`: 5.00 USD
- managed PostgreSQL database x1 `s-1vcpu-1gb`: 5.00 USD

Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.

## Verification evidence

- canary_run on 2026-09-20T21:55:28Z at revision `4f7cb9813c1f-dirty (CLI 4f7cb98)`: Destination side verified: the Rails pattern fixture deployed on Ample (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via `rails server` reading PORT on the ruby-3.4 template with RAILS_ENV=production) and its checks passed (the app built, started and answered on its public HTTPS URL with encrypted configuration delivered). The source-side export from Netlify web app is documented from the vendor's standard tooling and was not executed by this catalog's evidence. (expires 2027-03-19T21:55:28Z)

## Execution binding

No execution binding. This recipe is documentation only; nothing is executed automatically.