Rails 4.1 无法通过 capistrano 3 部署

使用 capistrano 部署 Rails 应用程序时，我遇到了非常奇怪的错误。有时部署，有时不部署。 例如，我向 css 添加一些内容（仅一个字符串），例如.my_some_class{width:10px}之后部署失败。在我添加这个之前 - 它部署正常。 我确信没有什么改变，因为我进行了实验性提交，其中只包含一串 css。 我的配置：

rails 4.1.0
ruby 2.1.1p76

gem 'capistrano-rails', group: :development
gem 'capistrano-rvm', group: :development
gem 'capistrano-bundler', group: :development

部署日志结束：

Tasks: TOP => deploy:assets:precompile
(See full trace by running task with --trace)
The deploy has failed with an error: #<SSHKit::Command::Failed: rake exit status: 137
rake stdout: Nothing written
rake stderr: SafeYAML Warning
  ----------------

  You appear to have an outdated version of libyaml (0.1.4) installed on your system.

  Prior to 0.1.6, libyaml is vulnerable to a heap overflow exploit from malicious YAML payloads.

  For more info, see:
  https://www.ruby-lang.org/en/news/2014/03/29/heap-overflow-in-yaml-uri-escape-parsing-cve-2014-2525/

  The easiest thing to do right now is probably to update Psych to the latest version and enable
  the 'bundled-libyaml' option, which will install a vendored libyaml with the vulnerability patched:

  gem install psych -- --enable-bundled-libyaml



I, [2014-04-30T09:42:41.121037 #12193]  INFO -- : Writing /var/www/default/releases/20140430134522/public/assets/Thumbs-82e32ea0cc1ce375db2805ceadd707ef.db
I, [2014-04-30T09:42:41.123108 #12193]  INFO -- : Writing /var/www/default/releases/20140430134522/public/assets/agency_no_logo-a8544e60b8a38abeb431c2eb5089f7c6.png
I, [2014-04-30T09:42:41.461121 #12193]  INFO -- : Writing /var/www/default/releases/20140430134522/public/assets/swipebox/img/loader-a66dde050b0b2447862919f2c4c37eda.gif

bash: line 1: 12193 Killed                  ( RAILS_ENV=production ~/.rvm/bin/rvm default do bundle exec rake assets:precompile )

正如上面所写，您可能没有足够的 RAM。

我通过在 Ubuntu 14.04 服务器上添加 SWAP 文件解决了问题：

在下面root:

dd if=/dev/zero of=/swapfile bs=1024 count=512k
mkswap /swapfile
swapon /swapfile

添加下一行到/etc/fstab:

 /swapfile       none    swap    sw      0       0 

and:

echo 0 > /proc/sys/vm/swappiness
sudo chown root:root /swapfile 
sudo chmod 0600 /swapfile

检查SWAP（可能需要重新加载）：

swapon -s 

— 如何在 Ubuntu 14.04 上添加交换 @ Digital Ocean Community