Thin

http://code.macournoyer.com/thin/

Install

as root:

gem install thin
thin install
update-rc.d -f thin defaults  (to have thin restart on reboot)

Config File

put this into /etc/thin/myapp.yml:

--- 
pid: tmp/pids/thin.pid
address: 0.0.0.0
timeout: 30
wait: 30
port: 4810
log: log/thin.log
max_conns: 1024
require: []

max_persistent_conns: 512
#environment: development
environment: production
servers: 4
daemonize: true
chdir: /var/www/myapp

Use with Apache

Set up modules:

a2enmod proxy
a2enmod proxy_balancer
a2enmod proxy_http
a2enmod rewrite