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Ruby on the server
This document discusses using Ruby on Rails web applications on servers. It recommends using Ruby Version Manager (RVM) to manage multiple Ruby versions and environments. Typical web applications use 100,000-200,000 memory slots total, with 2,000-10,000 objects per request. The falcon Ruby patch improves performance. Foreman can be used to launch Resque workers and schedulers, and export the configuration. Capistrano and restarting workers via signals allows for seamless code deployments.
Ruby on the server
- 1. Ruby on theServer Max out your rubies!
- 2. Ruby Version Manager Useit on the server! Multiple isolated Rubies Easy environment variables Easy install with patch integration setup/rvm.rb: https://gist.github.com/3946908
- 3. Ruby Garbage Collection Mark and Sweep, more or less: Stop the world Traverse and mark reference tree Free all unused objects (lazy = free) Still no free slots? Allocate 1.8 times more slots than on previous alloc
- 4. Typical Web Applications Small variations in used slots 100,000 - 200,000 slots in total 2,000 - 10,000 objects per request Most memory occupied by eternal (never freed) objects (code, classes, etc...)
- 5. Ruby 1.9.3-p286 Ruby 1.9.3GC is not copy-on-write friendly By default, 10,000 slots are allocated on startup 1.8 growth rate means Ruby is likely to allocate a lot more memory than needed!
- 6. falcon patch Copy-on-write friendlyGC Performance++ for require and Hash Supported in RVM (--patch falcon)
- 7. GC Configuration We wantto allocate enough memory, so that ruby never has to resize it’s heap Typically 100,000 to 200,000 initial slots RUBY_HEAP_MIN_SLOTS environment variable /usr/bin/time -l rails r "User.first(2000); pp GC.stat"
- 8. RAINBOWS Serves HTTP overa Unix socket Does not need root Master preloads app and forks workers Multiple net concurrency models Example config: https://gist.github.com/3946921
- 9. FOREMAN Process launcher Exports toUpstart, launchd and others Keeps developers happy!
- 10. FOREMAN: PROCFILE Environment-specific config called Procfile Advanced example: https://gist.github.com/3946937 # Simple (no rvm) Procfile web: bundle exec rainbows resque: bundle exec rake resque:work QUEUE=* scheduler: bundle exec rake resque:scheduler # Run with $ foreman start web # Export with $ sudo foreman export upstart /etc/init -u app_user -a app
- 11. Seamless deployments Tell Rainbowsmaster to restart (USR2) On spawning a new worker, kill an old one Extra memory requirement: 1 worker + 1 master Code here: https://gist.github.com/3946921
- 12. Capistrano Mostly “just works”with rvm-capistrano rvm_run command + restart_web task here: https://gist.github.com/3947004