page:guides:rails:cdn assets

Deliver public assets through CDN for Rails

Cdn assets for a Rails app on Ample. Verified on Rails: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. 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

• Deliver public assets through CDN for Rails
• Where can I host Deliver public assets through CDN built with Rails?
• I need a public-origin configuration, versioned asset build and observable cache behavior.

Resource 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.
• CDN: The CDN host serves objects from published buckets. It does not front app compute and is not a cache or key-value store.

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 bucket from ample bucket create with credentials passed as encrypted S3_* environment variables
• An Ample account token with servers:write, buckets: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. Publish a bucket for public assets: Publish only the asset bucket; upload versioned keys with an immutable Cache-Control header and build URLs from its public URL.
   • Command: ample bucket publish
3. Verify: Fetch the live URL and /p/versioned-static-assets on the example; on failure read the build and runtime logs.
   • Command: ample logs --kind build

Cost Estimate

• Currency: USD
• Monthly Amount: 5.0
• Basis: size prices from pricing.toml
• Components:
  • App server: size s-1vcpu-1gb, quantity 1.0, monthly amount 5.0

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.
• The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified.

Success Checks

• App responds on its public URL: Expect response on / with ample canary rails patterns
• Versioned-static-assets check from the example: Expect response on /p/versioned-static-assets to see the pattern fixture checks.

Example

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

Evidence Summary

• Summary: Rails pattern fixture deployed on Ample. Implemented as described above with versioned, immutable-cached assets.
• Observed At: 2026-09-20T21:55:28Z
• Last Verified At: 2026-09-20T21:55:28Z

Next Actions

• Browse the catalog index: GET /v1/catalog
• Search published recipes: POST /v1/catalog/search with body { "limit": 5, "query": "Deliver public assets through CDN for Rails" }
• Prepare a side-effect-free deployment plan: POST /v1/catalog/plan with appropriate body inputs.