AWS Elastic Beanstalk Rails Bundler Failing - ruby-on-rails

Question

I'm using the eb CLI to install my rails app on AWS. I've gotten a test one to work before, but now I'm trying to deploy some actual code that I wrote. When I do git aws.push, the update fails. "eb logs" command shows that the bundler failed.
I am running this on 64bit Amazon Linux 2014.03 v1.0.0 running Ruby 2.1 (Puma)
Fetching source index from https://rubygems.org/
Using rake (10.3.2)
Using i18n (0.6.11)
Using minitest (4.7.5)
Using multi_json (1.10.1)
Using thread_safe (0.3.4)
Using tzinfo (0.3.41)
Using activesupport (4.0.8)
Using builder (3.1.4)
Using erubis (2.7.0)
Using rack (1.5.2)
Using rack-test (0.6.2)
Using actionpack (4.0.8)
Using mime-types (1.25.1)
Using polyglot (0.3.5)
Using treetop (1.4.15)
Using mail (2.5.4)
Using actionmailer (4.0.8)
Using activemodel (4.0.8)
Using active_model_serializers (0.9.0)
Using activerecord-deprecated_finders (1.0.3)
Using arel (4.0.2)
Using activerecord (4.0.8)
Using addressable (2.3.6)
Using execjs (2.2.1)
Using autoprefixer-rails (3.0.1.20140826)
Installing bcrypt (3.1.7)
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
/opt/rubies/ruby-2.1.2/bin/ruby extconf.rb
Cannot allocate memory - /opt/rubies/ruby-2.1.2/bin/ruby extconf.rb 2>&1
Gem files will remain installed in /opt/rubies/ruby-2.1.2/lib/ruby/gems/2.1.0/gems/bcrypt-3.1.7 for inspection.
Results logged to /opt/rubies/ruby-2.1.2/lib/ruby/gems/2.1.0/extensions/x86_64-linux/2.1.0-static/bcrypt-3.1.7/gem_make.out
An error occurred while installing bcrypt (3.1.7), and Bundler cannot continue.
Make sure that `gem install bcrypt -v '3.1.7'` succeeds before bundling.
2014-09-03 00:22:36,561 [ERROR] (3331 MainThread) [directoryHooksExecutor.py-33] [root directoryHooksExecutor error] Script /opt/elasticbeanstalk/hooks/appdeploy/pre/10_bundle_install.sh failed with returncode 5
I'm not calling bcrypt in my gem file either. It must be a dependency of the sorcery gem.
I've attempted to use the "bundle package" for the vendor/cache trick, but it kept saying some gems were missing on AWS. As you can tell, I'm fairly new to not only elastic beanstalk/aws but to rails as well, so I could just be doing something totally wrong.
Also, when I remove bcrypt references (which I'm sure will break something) in the gemfile.lock, it just throws the same error on a different gem later on (ffi). I'm sure there are many gems that it will eventually throw the error on if I just manage to fix the issue one gem at a time.

Answer 1

The error is actually caused by instance running out of memory while running make:
Cannot allocate memory - /opt/rubies/ruby-2.1.2/bin/ruby extconf.rb 2>&1
More than likely you are running a micro instance--bump it up to a larger instance size and it should build reliably.
Rohit is right though in his answer that missing system packages are often a cause of gems failing to install in Elastic Beanstalk.

Answer 2

So there may be some dependencies on C libraries that are required for gem install bcrypt -v '3.1.7'. You can install native dependencies using yum and ebextensions.
You can use ebextensions to install yum packages required for gem install to succeed. Create a file called .ebextensions/01-yum.config in your app source and put the following contents in it.
packages:
yum:
<required-native-dependency>: []
This file is in YAML format so indentation is important.
Read more about pacakges section of ebextensions here:
http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/customize-containers-ec2.html#customize-containers-format-packages