page:guides:rails:schema changes

Apply database schema changes for Rails

Summary

Schema changes for a Rails app on Ample. Verified on Rails: a --release-command migration ran before activation and its marker was readable by the live app (migrated=release-ok). Build and start: 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.

Representative Queries

• Apply database schema changes for Rails
• Where can I host Apply database schema changes built with Rails?
• I need a framework-specific schema migration and rollback procedure; no managed migration service is assumed.

Resource Requirements

• primitive:compute
• primitive:postgres

Infrastructure Requirements

1. Compute:
   • Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
2. Postgres:
   • Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

Framework

Rails

Workload

Apply database schema changes

Release Status

Published

Support Status

Verified

Execution Status

Ready

Prerequisites

• A Rails project (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)
• A PostgreSQL driver reading DATABASE_URL at runtime
• An Ample account token with servers:write, databases:read

Workflow Steps

1. Build and start:
   • 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; the server must bind 0.0.0.0 on PORT.
2. Run migrations as the release command:
   • Ample runs the command before activation and fails the release if it exits non-zero; keep migrations idempotent.
   • Command: ample deploy . --name --public --release-command "python3 migrate.py"
3. Verify:
   • Fetch the live URL and /p/migrated on the example; on failure read the build and runtime logs.
   • Command: ample logs --kind build

Examples

• Rails pattern fixture:
  • Verified schema changes on Rails. Reference: tests/deploy-canaries/rails-patterns

Success Checks

1. App responds on its public URL:
   • Expect: ample canary rails patterns
2. Migrated check from the example:
   • Expect: see the pattern fixture checks

Limitations

• Verified on the ruby-3.4 template at s-1vcpu-1gb; other sizes and Rails major versions are not verified.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Authoritative: true
• Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
• Components:
  1. App server:
     • Size: s-1vcpu-1gb
     • Quantity: 1.0
     • Monthly Amount: 5.0
  2. Managed PostgreSQL database:
     • Size: s-1vcpu-1gb
     • Quantity: 1.0
     • Monthly Amount: 5.0
• Note: Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

Evidence Summary

• Canary run:
  • Summary: Rails pattern fixture deployed on Ample.
  • Observed At: 2026-09-20T21:55:28Z
  • Implementation Revision: 4f7cb9813c1f-dirty (CLI 4f7cb98)
  • Expires At: 2027-03-19T21:55:28Z
  • Scope: checks, template: ruby-3.4

Last Verified At

2026-09-20T21:55:28Z

Unknowns

• Region availability is unknown until a verified region fact is recorded.
• Compliance attestations are unknown; none are claimed.

Formats

• HTML: https://ample.computer/guides/rails/schema-changes
• Markdown: https://ample.computer/guides/rails/schema-changes.md
• JSON: https://api.ample.computer/v1/catalog/recipes/page%3Aguides%3Arails%3Aschema-changes

Next Actions

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   • Operation ID: search_recipes
   • Method: POST
   • Relative Path: /v1/catalog/search
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   • Parameters: Limit: 5, Query: Apply database schema changes for Rails
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