Host admin dashboard with Rails: public profile assets

Summary

Deploy a admin dashboard built with Rails on Ample using the public image delivery pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables, and a published bucket serves public assets from the CDN host. Verified on Rails: public objects in a published bucket served from the CDN URL, kept separate from private objects in an unpublished bucket that require authorization (private=ok only for the allowed role). Not separately tested: your image processing and profile-media rules; treat the admin dashboard-specific behavior as your application code.

Infrastructure requirements

• Compute: 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: 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.)
• S3-compatible object storage: verified (Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.)
• CDN: verified (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 that builds and starts with the documented commands (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 (auto-provisioned when omitted, or supplied with --env)
• A bucket from ample bucket create with its credentials passed as encrypted S3_* environment variables and a second, published bucket for public assets (CDN_*)
• An Ample account token with servers:write, databases:read, buckets: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. 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. Implement the pattern on PostgreSQL. The fixture's module implements public image delivery: public objects in a published bucket served from the CDN URL, kept separate from private objects in an unpublished bucket that require authorization (private=ok only for the allowed role). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. Wire object storage. Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket. Publish only the bucket that serves public assets and reference its CDN URL.

4. Deploy. Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.

   ample deploy . --name <app-name> --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=... --env CDN_PUBLIC_URL=...
   

5. Verify. Fetch the live URL and the pattern self-test route(s) (/p/public-media-library, /p/private-document-library) from the example; then run your own checks. On failure read ample logs <deployment_id> --kind build then --kind runtime.

   ample logs <deployment_id> --kind build
   

Tested examples

• Rails pattern fixture (tests/deploy-canaries/rails-patterns): Multi-pattern Rails app whose public image delivery module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

Success checks

• app responds on its public URL (/ on the live URL, expect ample canary rails patterns)
• public-media-library self-test (/p/public-media-library on the live URL, expect a CDN URL whose content is served publicly)
• private-document-library self-test (/p/private-document-library on the live URL, expect private=ok (with ?role=owner; 401 without, 403 for viewer))

Limitations

• Verified on the ruby-3.4 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Rails major versions are not verified.
• The admin dashboard itself (your image processing and profile-media rules) is application code and was not separately tested; the pattern checks are what was verified.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.
• PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not.
• The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified (the fixture sets Cache-Control on upload and versions keys).

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

Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

Verification evidence

• canary_run on 2026-09-20T21:55:28Z at revision 4f7cb9813c1f-dirty (CLI 4f7cb98): 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); checks passed for public-media-library, private-document-library and configuration-secrets. Pattern proof: public objects in a published bucket served from the CDN URL, kept separate from private objects in an unpublished bucket that require authorization (private=ok only for the allowed role). (expires 2027-03-19T21:55:28Z)
• canary_run on 2026-09-20T21:55:28Z at revision 4f7cb9813c1f-dirty (CLI 4f7cb98): The same Rails app deployed with a --release-command migration; the marker it created was readable after activation. (expires 2027-03-19T21:55:28Z)

Last verified: 2026-09-20T21:55:28Z

Execution binding

MCP tool ample_deploy (registry mcp:ample_deploy), schema hash 876465fce906da0c observed 2026-09-21T03:19:59.461917+00:00 at revision 49962bcade4f, binding state current, required scopes: servers:write, databases:read, buckets:read.