01 / 03
Modernize the Gemfile first
Before touching infrastructure, bump Ruby to 3.3 and Padrino to the latest 0.16.x. Run the test suite. Fix the deprecation warnings. This is 80% of the work.
// framework · padrino
Padrino: Sinatra, all grown up.
Admin panels, mailers, and mountable subapps — deployed with the same care as any modern Ruby stack.
Padrino occupies a lovely niche: bigger than Sinatra, smaller than Rails, and still shipping. Most Padrino apps in the wild are 5–10 years old — this guide focuses on migrating them onto a modern container platform without a rewrite.
2.7 → 3.3
typical Ruby version bump
2–5 days
container migration effort
0
downtime required
02 / 03
Containerize without rewriting
Padrino apps often assume writable local directories for tmp/ and log/. Redirect logs to stdout and mount tmp/ as tmpfs — no code changes required.
ruby# config/boots.rb (bottom) Padrino.logger = Padrino::Logger.new( stream: $stdout, log_level: :info, format_datetime: "%FT%T%z " )
03 / 03
Subapps as one container
Padrino's mountable subapps all share a single process. Don't try to split them into separate services during the containerization step — do it later, if at all.
Gotchas we learned the hard way
- !The Padrino admin uses cookie-based sessions signed with a secret. Rotate it via env var, not by editing config/apps.rb.
- !Older Padrino apps often use `padrino rake …` — use `bundle exec rake …` in containers, since padrino rake wraps in a way that eats signals.
- !Legacy assets: precompile with `padrino rake sprockets:precompile` at image build. Do NOT try to migrate to Propshaft in the same PR as the containerization.
Official resources
Docs, repos, and training materials for this framework.
Related guides
→ guide
Cloud · Heroku
Where Rails grew up. Still the fastest zero-to-production experience for a solo founder or small team, in 2026.
→ guide
Cloud · AWS
The most control, the most services, the most footguns. Here's the opinionated path that keeps a Ruby app boring and stable.
→ guide
Cloud · Hatchbox
By Chris Oliver of GoRails. A managed control plane over VMs you own — Heroku ergonomics on infrastructure you control end to end.
→ guide
Framework · Sinatra
The 40-line Dockerfile framework. Perfect for internal APIs, webhooks, and 'we just need one endpoint' services.
→ guide
Framework · Rails
The majestic monolith is back, and it deploys better than ever. Kamal 2, Solid stack, Propshaft — no Node, no Redis, no Nginx if you don't want them.
Ready?
Move Padrino to the cloud
Heroku is often the gentlest first step — the buildpack still works. Then containerize when you're ready to move.