sudo gem install -v=2.3.9 rails
Password:
ERROR:  Could not find a valid gem 'rails' (= 2.3.9) in any repository
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    too many connection resets (http://production.s3.rubygems.org/latest_specs.4.8.gz)

或

ERROR: While executing gem ... (Gem::DependencyError)
  Unable to resolve dependencies: rails requires activesupport (= 3.0.5), actionpack (= 3.0.5), activerecord (= 3.0.5), activeresource (= 3.0.5), actionmailer (= 3.0.5), railties (= 3.0.5), bundler (~> 1.0)

google了半天（期間google中短NNN次），才明天了現在使用rubygems 安裝gem也得開代理了。。。

要使用加了代理的命令：

sudo gem install rails -p http://127.0.0.1:8118

現在rubygems好像只支持http代理。 如果你使用的是socks代理，可以通過Privoxy（支持linux和mac)這個軟件來搞一個http代理 通道， 詳細參看這個教程。

安裝unicorn:

sudo gem install unicorn


創建網站配置文件(myproject是項目名稱):

sudo mkdir /etc/unicorn
cd /etc/unicorn/
sudo nano /etc/unicorn/myproject.conf


內容如下：

RAILS_ROOT=/www/myproject
RAILS_ENV=production


在網站里再創建一個unicorn配置文件

nano /www/myproject/config/unicorn.rb


內容如下：

# Minimal sample configuration file for Unicorn (not Rack) when used
# with daemonization (unicorn -D) started in your working directory.
#
# See http://unicorn.bogomips.org/Unicorn/Configurator.html for complete
# documentation.
# See also http://unicorn.bogomips.org/examples/unicorn.conf.rb for
# a more verbose configuration using more features.

app_path = "/www/myproject"

listen 8080 # by default Unicorn listens on port 8080
worker_processes 2 # this should be >= nr_cpus
pid "#{app_path}/tmp/pids/unicorn.pid"
stderr_path "#{app_path}/log/unicorn.log"
stdout_path "#{app_path}/log/unicorn.log"


設置unicorn啟動腳本：

sudo nano /etc/init.d/unicorn_init

腳本內容：

#!/bin/sh
#
# init.d script for single or multiple unicorn installations. Expects at least one .conf
# file in /etc/unicorn
#
# Modified by jay@gooby.org http://github.com/jaygooby
# based on http://gist.github.com/308216 by http://github.com/mguterl
#
## A sample /etc/unicorn/my_app.conf
##
## RAILS_ENV=production
## RAILS_ROOT=/var/apps/www/my_app/current
#
# This configures a unicorn master for your app at /var/apps/www/my_app/current running in
# production mode. It will read config/unicorn.rb for further set up.
#
# You should ensure different ports or sockets are set in each config/unicorn.rb if
# you are running more than one master concurrently.
#
# If you call this script without any config parameters, it will attempt to run the
# init command for all your unicorn configurations listed in /etc/unicorn/*.conf
#
# /etc/init.d/unicorn start # starts all unicorns
#
# If you specify a particular config, it will only operate on that one
#
# /etc/init.d/unicorn start /etc/unicorn/my_app.conf

set -e

sig () {
test -s "$PID" && kill -$1 `cat "$PID"`
}

ARGS="$1 $2"
start_stop $ARGS

注意將裡面的/usr/bin/unicorn_rails 換成你系統中unicorn_rails程序的實際路徑。

設置unicorn_init文件屬性:

sudo chmod 755 /etc/init.d/unicorn_init


啟動unicorn:

/etc/init.d/unicorn_init


修改nginx的配置文件，加入unicorn的代理設置：

upstream myproject_mongrel {
server 127.0.0.1:8080 fail_timeout=0;
}

這部分跟使用mongrel的類似的。

這樣unicorn的設置就完成了。 剛設置好，感覺unicorn跟mongrel一樣， 都是比較吃內存的， 一啟動就佔了50M. 不知道會不會也像mongrel一樣把內存吃爆， 會得話得設置監控軟件（如god）看住它。