We're using bundler 1.0.10 which has bug:

https://github.com/carlhuda/bundler/pull/1027

If your Gemfile uses gemspec (so someone developing a Rails engine gem, like the Console team), when you deploy to OpenShift and run 'bundler install --deployment' it chokes and dies with an error about the source changing.  The gems don't get installed and the app won't start.  I think a few users have hit this as well if they had local gems they were installing.

remote: Bundling RubyGems based on Gemfile/Gemfile.lock to repo/vendor/bundle with 'bundle install --deployment'
remote: You have modified your Gemfile in development but did not check
remote: the resulting snapshot (Gemfile.lock) into version control
remote: 
remote: You have added to the Gemfile:
remote: * source: source at /var/lib/stickshift/d742ae50e0ee4ef8a648be189bb00380/console/runtime/repo
remote: 
remote: You have deleted from the Gemfile:
remote: * source: source at .
remote: Precompiling with 'bundle exec rake assets:precompile'
remote: Could not find rake-0.9.2.2 in any of the sources
remote: Running .openshift/action_hooks/build
remote: Running .openshift/action_hooks/deploy

SSH into the remote machine, run bundle install --deployment from the repo dir, and see:

[console-claytondev.rhcloud.com repo]\> bundle install --deployment
You have modified your Gemfile in development but did not check
the resulting snapshot (Gemfile.lock) into version control

You have added to the Gemfile:
* source: source at /var/lib/stickshift/d742ae50e0ee4ef8a648be189bb00380/console/runtime/repo

You have deleted from the Gemfile:
* source: source at .

Gemfile:
source 'http://rubygems.org'

gemspec

console.spec:
$:.push File.expand_path("../lib", __FILE__)

Gem::Specification.new do |s|
...
s.add_dependency ...
end

Since proper functioning of bundler is so critical to Ruby cartridges, we should upgrade to at least 1.0.12 (which fixes this) or a much newer rev (to get the latest).  We should be fairly aggressive with bundler updates.