page:guides:rails:database connection

Connect Postgres for Rails

Summary

Database connection for a Rails app on Ample. Verified on Rails: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=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

• Connect Postgres for Rails
• Where can I host Connect Postgres built with Rails?
• I need driver setup, connection settings, secret handling and a real connection test.

Resource Requirements

• primitive:compute
• primitive:postgres

Infrastructure Requirements

• Compute: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
• 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.

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. Read DATABASE_URL at runtime: Open connections from the environment inside handlers or a pool; omit DATABASE_URL to auto-provision a managed database or pass --env DATABASE_URL=... for an existing one.
3. Verify: Fetch the live URL and /p/relational-records on the example; on failure read the build and runtime logs. Command: ample logs --kind build

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.

Success Checks

• App responds on its public URL: HTTP GET / expects response: ample canary rails patterns
• Relational-records check from the example: HTTP GET /p/relational-records expects to see the pattern fixture checks.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Components:
  • App server: s-1vcpu-1gb - 1.0 - $5.0/month
  • Managed PostgreSQL database: s-1vcpu-1gb - 1.0 - $5.0/month
• Note: Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

Examples

• Rails pattern fixture: Verified database connection on Rails. Source: tests/deploy-canaries/rails-patterns.

Additional Information

• Last Verified At: 2026-09-20T21:55:28Z
• MCP Binding: Current
• Unknowns: Region availability and compliance attestations are unknown; none are claimed.
• Formats:
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