使用Amazon RDS进行部署时，Capistrano超时

Question

我似乎无法让Capistrano在AmazonRDS上表现出色。我到处寻找有关正确设置此设置的任何信息，但没有找到任何信息。现在，当我cap deploy时，该过程超时。

这是我的deploy.rb:

set :deploy_to, "/opt/bitnami/apps/annarbortshirtcompany.com/cms/" 
set :scm, :git
set :repository,  "ssh://user@ec2-repository.compute-1.amazonaws.com/~/repo/cms.git"
set :deploy_via, :remote_cache

set :user, "user"
ssh_options[:keys] = [File.join(ENV["HOME"], "EC2", "admin.pem")]
ssh_options[:forward_agent] = true
set :branch, "master"
set :use_sudo, true

set :location, "ec2-webserver.compute-1.amazonaws.com"
role :web, location
role :app, location
role :db, "cmsinstance.c7r8frl6npxn.us-east-1.rds.amazonaws.com", :primary => true

# If you are using Passenger mod_rails uncomment this:
namespace :deploy do
  task :start do ; end
  task :stop do ; end
  task :restart, :roles => :app, :except => { :no_release => true } do
    run "#{try_sudo} touch #{File.join(current_path,'tmp','restart.txt')}"
  end
end

RDS数据库实例的用户名不同于此处设置的SSH用户名，但在我的database.yml中定义。我认为capistrano可能不会读取此内容，但不知道如何实现。

当我“上限部署”时:

ubuntu@ubuntu-VirtualBox:~/RailsApps/cms$ cap deploy
  * executing `deploy'
  * executing `deploy:update'
 ** transaction: start
  * executing `deploy:update_code'
    updating the cached checkout on all servers
    executing locally: "git ls-remote ssh://user@ec2-repository.compute-1.amazonaws.com/~/repo/cms.git master"
    command finished in 1590ms
  * executing "if [ -d /app-directory/shared/cached-copy ]; then cd /app-directory/shared/cached-copy && git fetch -q origin && git fetch --tags -q origin && git reset -q --hard ffc4ec7762566f801c4a9140aa3980dc71e3d06f && git clean -q -d -x -f; else git clone -q  ssh://user@ec2-repository.amazonaws.com/~/repo/cms.git /app-directory/shared/cached-copy && cd /app-directory/shared/cached-copy && git checkout -q -b deploy ffc4ec7762566f801c4a9140aa3980dc71e3d06f; fi"
    servers: ["ec2-webserver.compute-1.amazonaws.com", "dbinstance.us-east1.rds.amazonaws.com"]
*** [deploy:update_code] rolling back
  * executing "rm -rf /app-directory/releases/20110607161612; true"
    servers: ["ec2-webserver.compute-1.amazonaws.com", "dbinstance.us-east1.rds.amazonaws.com"]
 ** [deploy:update_code] exception while rolling back: Capistrano::ConnectionError, connection failed for: dbinstance.us-east1.rds.amazonaws.com (Errno::ETIMEDOUT: Connection timed out - connect(2))
    connection failed for: dbinstance.us-east1.rds.amazonaws.com (Errno::ETIMEDOUT: Connection timed out - connect(2))

为什么要“更新所有服务器上的缓存结帐”？此时甚至不需要DB服务器。我为如何解决这个问题而感到困惑。希望有人可以指出正确的方向!

Answer 1

我确实遇到了这个问题，并为此苦苦挣扎，因为我不好意思说这是一个5或6个小时的好时机。最后，当我意识到问题出在哪里时，我感觉就像是在自欺欺人，因为我曾经知道这一点，但却忘记了它。这是问题的症结，从deploy.rb的这一部分开始:

set :location, "ec2-webserver.compute-1.amazonaws.com"
role :web, location
role :app, location
role :db, "cmsinstance.c7r8frl6npxn.us-east-1.rds.amazonaws.com", :primary => true

当您定义Capistrano的计算机角色时，实际上并没有确定哪些计算机将扮演特定的角色……而是要确定在为角色应用部署配方时Capistrano代码将在哪些计算机上运行。因此，定义:db角色时，您要指向EC2实例，而不是RDS实例。您不能使用RDS机器，因此Capistrano无法在其中运行配方。相反，将:db指向与您指向:web和:app相同的机器，即

set :location, "ec2-webserver.compute-1.amazonaws.com"
role :web, location
role :app, location
role :db, location, :primary => true

RDS机器如何参与其中？好吧，这是database.yml文件，该文件指示哪台计算机实际在运行SQL的RDBMS上运行。您只需要确保为目标数据库设置了host:值，例如:

production:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: <your_db>_production
  pool: 5
  username: <username>
  password: <password>
  host: cmsinstance.c7r8frl6npxn.us-east-1.rds.amazonaws.com

有道理？

我希望这可以避免别人遇到的挫折感。

大卫