Passenger standalone fails to start with capistano - ruby-on-rails

Question

I'm a bit of a newbie when it comes to deploying and related things, so please be lenient.
I'm building a staging server for a bunch of hobby projects, and to do that, I'll need to
Support multiple Ruby versions
Support multiple running rails/other applications
Support multiple databases and related software
I also want the deploy script to allow deploying to production, if the day ever comes.
This background necessitates the use of RVM, Capistrano-multistage and Passenger Standalone (the other option being Mongrel, but as I wish to use Passenger in production, I figured it'd be safer to use Passenger in staging too). All of this makes deployment a little hairy.
I've gotten things cobbled together quite nicely, and everything else seems to work, but for some reason Passenger fails to start when commanded to do so from Capistrano. If I SSH into the box and type the command in myself it works nicely. What's wrong?
To aid you in your efforts to help me, here is a copy of my config/deploy.rb
set :application, "Appname"
set :repository, "path-to-git-repo-over-ssh"
set :scm, :git
default_run_options[:pty] = true
set :rvm_ruby_string, ENV['GEM_HOME'].gsub(/.*\//,"")
set :rvm_install_ruby_params, '--1.9' # for jruby/rbx default to 1.9 mode
set :rvm_install_pkgs, %w[libyaml openssl] # package list from https://rvm.io/packages
set :rvm_install_ruby_params, '--with-opt-dir=/usr/local/rvm/usr' # package support
set :use_sudo, false
before 'deploy:setup', 'rvm:install_rvm' # install RVM
before 'deploy:setup', 'rvm:install_ruby' # install Ruby and create gemset
require "rvm/capistrano"
require "bundler/capistrano"
require 'sidekiq/capistrano'
set :deploy_via, :remote_cache
set :stages, %w(staging production)
set :default_stage, "staging"
require 'capistrano/ext/multistage'
set :rails_env, lambda { stage }
set :startcmd, lambda { "cd #{current_path} && bundle exec passenger start -d -p #{passenger_port} -e #{rails_env} --pid-file=#{current_path}/tmp/pids/passenger.#{passenger_port}.pid #{current_path}" }
namespace :deploy do
task :stop do
run("cd #{current_path} && bundle exec passenger stop -p #{passenger_port}")
end
task :restart do
run("cd #{current_path} && touch tmp/restart.txt")
end
task :start do
run("#{startcmd}")
end
end
after "deploy:update_code" do
run "(echo \"#reboot /bin/bash -l -c '#{startcmd}' >>log/boot.out 2>>log/boot.err # from capistrano \" && cat #{release_path}/crontab.#{stage}) | crontab -"
end
And here is config/deploy/staging.rb
set :deploy_to, "/var/www/appname"
set :user, 'app-specific-user'
set :password, 'super-secret-password'
set :domain, '1.2.3.4'
server domain, :app, :web
role :db, domain, :primary => true
set :passenger_port, 1234

Answer 1

Well bloody hell.
On complete hunch, I removed the
default_run_options[:pty] = true
Setting from the file, and like magic it started working. Now if only someone would tell me why.