问题

用 capistrano 一键部署。 我明明是已经装了 passenger 了的。

 $ ps aux | grep flying-passenger
    deploy   27378  0.0  0.0  13416   936 pts/4    S+   11:11   0:00 grep --color=auto flying-passenger

$ which passenger-config
   /home/deploy/.rvm/gems/ruby-2.2.3/bin/passenger-config

$ cd /home/deploy/.rvm/gems/ruby-2.2.3/gems
$ ls
bundle-0.0.1  bundler-1.10.6  passenger-5.0.16  rack-1.6.4

但部署过程被中断，提示说

cap aborted!
  SSHKit::Runner::ExecuteError: Exception while executing as deploy@xxx.xxx.xxx.xxx: passenger exit status: 1
  passenger stdout: : Could not find 'passenger' (>= 0) among 14 total gem(s) (Gem::LoadError)
  Checked in 'GEM_PATH=/home/deploy/.rvm/gems/ruby-2.2.3:/home/deploy/.rvm/gems/ruby-2.2.3@global',
          execute `gem env` for more information

  passenger stderr: Nothing written

  Tasks: TOP => passenger:restart
  (See full trace by running task with --trace)

尝试用

$ passenger start -a 0.0.0.0  -d -e production

无效。

以前出现过其它原因无法启动 passenger 中断情况，我根据教程passenger-config restart-app with capistrano，处理过

# 本机代码修改
 # deploy.rb
 set :rvm_map_bins, fetch(:rvm_map_bins, []).push('rvmsudo')
 set :passenger_restart_command, 'rvmsudo passenger-config restart-app'

但这次不是同样的问题。

不太明白。难道是我 passenger 安装的位置不对吗？

$ gem search passenger

*** REMOTE GEMS ***

balepc-zombie_passenger_killer (0.2.1)
blazing-passenger (0.2.4)
cap_passenger_ping (0.9.0)
capistrano-passenger (0.1.1)
capistrano-passenger5-nginx (0.0.1)
check_passenger (1.0)
cijoe_passenger (0.1.2)
colouringcode-passenger (0.2)
genki-passenger-restart (0.0.2)
guard-passenger (0.6.1)
karsthammer-passenger (2.2.4)
passenger (5.0.16)
passenger-jmazzi (2.2.10)
passenger-oob-gc (0.0.1)
passenger-rails (0.0.2)
passenger-recipes (0.1.2)
passenger_debugger (0.1.3)
passenger_dudemeister (3.0.1)
passenger_dyno (0.0.2)
passenger_mon (0.3.0)
passenger_monit (0.1.1)
passenger_reaper (0.0.2)
passenger_status (0.0.2)
peppyheppy-cpanel-passenger (0.0.3.1)
railsware-passenger (3.0.2.1)
redinger-passenger_debugger (0.1.1)
rockdog-passenger (0.0.1)
ruby-debug-passenger (0.2.0)
yspassenger (3.0.12)
zombie_passenger_killer (0.4.0)

$ gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 2.4.8
  - RUBY VERSION: 2.2.3 (2015-08-18 patchlevel 173) [x86_64-linux]
  - INSTALLATION DIRECTORY: /home/deploy/.rvm/gems/ruby-2.2.3
  - RUBY EXECUTABLE: /home/deploy/.rvm/rubies/ruby-2.2.3/bin/ruby
  - EXECUTABLE DIRECTORY: /home/deploy/.rvm/gems/ruby-2.2.3/bin
  - SPEC CACHE DIRECTORY: /home/deploy/.gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /home/deploy/.rvm/rubies/ruby-2.2.3/etc
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-linux
  - GEM PATHS:
     - /home/deploy/.rvm/gems/ruby-2.2.3
     - /home/deploy/.rvm/gems/ruby-2.2.3@global
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
     - :sources => ["https://ruby.taobao.org"]
  - REMOTE SOURCES:
     - https://ruby.taobao.org
  - SHELL PATH:
     - /home/deploy/.rvm/gems/ruby-2.2.3/bin
     - /home/deploy/.rvm/gems/ruby-2.2.3@global/bin
     - /home/deploy/.rvm/rubies/ruby-2.2.3/bin
     - /usr/local/sbin
     - /usr/local/bin
     - /usr/sbin
     - /usr/bin
     - /sbin
     - /bin
     - /usr/games
     - /usr/local/games
     - /home/deploy/.rvm/bin
     - /home/deploy/.rvm/bin

能找到的吧？

解决方案

感觉有点出了问题靠猜，最终起作用的可能有两个因素，又或是殊途同归。 一是按@ huacnlee 说的把 passenger 加进 gemfile，但一开始没起作用，我就又进服务器项目地址

 gem install passenger

passenger start -a 0.0.0.0  -d -e production

这时候再 cap production deploy，又提示我有两个 passenger 实例正在运行，只好又passenger stop掉一个。

已经用 cap 部署过很多很多项目了，这次问题出得很莫名其妙，难道因为我以前都是在项目目录内 gem install passenger，而这次可能直接在其它目录里？ 解决得也有点莫名其妙……

P.S. 因为是节前部署的，后来就忘了。 我想问题很可能出在之前，我忘了进项目目录去gem install passenger，而是在根目录下安装了。所以 gem 的位置就不对了…… 恩，这大概就是基础不扎实的表现……没有意识到在不同路径下装 gem 可能带来不同的结果……