实例

IP:192.168.1.100
    开发服务器,capistrano 发布服务器
    svn地址:svn://192.168.1.100/svnweb
    svn发布目录:/app/dev_public
IP:192.168.1.200 
    web服务器

    web目录: /opt/webroot/ 

capistrano 发布原理
使用svn用户将svn项目svn://192.168.1.100/svnweb checkout 到/tmp/20130108***下通过sftp将/tmp/20130108***文件打为tgz,并上传到web服务器tmp/20130108***.tgz,并将/tmp/20130108***.tgz解压到web服务器/opt/webroot/目录。 

安装
capistrano 基于Ruby管理工具(RubyGames)安装,先安装Ruby,再安装RubyGames,最后安装Capistrano
Ruby下载                  http://ishare.iask.sina.com.cn/download/explain.php?fileid=9554760
RubyGames下载         http://files.rubyforge.vm.bytemark.co.uk/rubygems/rubygems-1.8.9.tgz 
Ruby安装
# tar jxf ruby-1.9.2-p0.tar.bz2
# cd ruby-1.9.2-p0
# ./configure
# make && make install 
RubyGames安装
# tar zxv rubygems-1.8.9.tgz
# cd rubygems-1.8.9

/usr/local/bin/ruby setup.rb 

Capistrano安装
# gem install Capistrano  
配置 
# cd /home/dev_public
# capify . (注意后面的.号)
capify .执行后会在目录里Capfile文件和一个config文件夹,config文件夹里deploy.rb配置文件。
 /home/dev_public
|-- Capfile
`-- config
    `-- deploy.rb
 
修改deploy.rb配置文件,内容如下:
# vi   /app/dev_public/config/deploy.rb 
set :application, "dev_public01"
set :repository, "svn://192.168.1.100/svnweb"
set :scm, :subversion
set :scm_username, 'dev_public'
set :scm_password, 'dev_public'
set :checkout, "export"
role :web, "192.168.1.200"
#role :db,  "192.168.1.201"
set :deploy_to, "/opt/webroot/"
set :deploy_via, :copy
set :user, "root"
set :runner, "devpass"

set :password, "devpass"
set :port,     2222  

set :use_sudo, true
set :keep_releases, 3
namespace :deploy do
     task :restart, :roles => :web do
         run "sudo chown www:www -R /opt/webroot/"
     end
end
 
配置说明:
set :application         定义项目名称
set :repository          svn地址
set :scm                  定义svn名称
set :scm_username         svn用户名
set :scm_password         svn密码
set :checkout             svn执行方式
role :web                 定义web服务器地址,可定义多个
set :deploy_to            定义web服务器目录
set :deploy_via           定义部署文件,copy  
set :user                 web服务器登陆用户名,也可使用ssh密钥登陆
set :runner               web服务器运行用户名    
set :password             web服务器密码
set :port         web服务器ssh端口
set :use_sudo             使用sudo
set :keep_releases        存储版本个数,执行cap deploy:cleanup清理版本时,保留的版本个数
发布版本时,在web服务器上执行相关命令
namespace :deploy do
     task :restart, :roles => :web do
         run "sudo chown www:www -R /opt/webroot/"
     end
end
 
注意将web服务器的/etc/sudoers文件中的 Defaults    requiretty 注释掉,否则在执行cap deploy:setup时会报以下错误。
sudo: sorry, you must have a tty to run sudo 
发布 
# cd /app/dev_public
# cap deploy:setup         #在web服务器上建相应目录,为发布代码做准备
/opt/webroot/
|-- current
|-- releases
`-- shared
    |-- log
    |-- pids
    `-- system
# cap deploy:check            #检查web服务器上文件夹权限
# cap deploy                  #代码发布 
cap deploy:rollback           #可以快速回滚到上一版本
cap deploy:cleanup            #清理版本,且保留版本数量与deploy.rb配置文件set :keep_releases参数有关。 
# cap -vT 可查看相关参数,如下:
cap deploy                   # Deploys your project.
cap deploy:check             # Test deployment dependencies.
cap deploy:cleanup           # Clean up old releases.
cap deploy:cold              # Deploys and starts a `cold' application.
cap deploy:create_symlink    # Updates the symlink to the most recently deplo...
cap deploy:finalize_update   # [internal] Touches up the released code.
cap deploy:migrate           # Run the migrate rake task.
cap deploy:migrations        # Deploy and run pending migrations.
cap deploy:pending           # Displays the commits since your last deploy.
cap deploy:pending:diff      # Displays the `diff' since your last deploy.
cap deploy:restart           # 
cap deploy:rollback          # Rolls back to a previous version and restarts.
cap deploy:rollback:cleanup  # [internal] Removes the most recently deployed ...
cap deploy:rollback:code     # Rolls back to the previously deployed version.
cap deploy:rollback:revision # [internal] Points the current symlink at the p...
cap deploy:setup             # Prepares one or more servers for deployment.
cap deploy:start             # Blank task exists as a hook into which to inst...
cap deploy:stop              # Blank task exists as a hook into which to inst...
cap deploy:symlink           # Deprecated API.
cap deploy:update            # Copies your project and updates the symlink.
cap deploy:update_code       # Copies your project to the remote servers.
cap deploy:upload            # Copy files to the currently deployed version.
cap invoke                   # Invoke a single command on the remote servers.
cap shell                    # Begin an interactive Capistrano session