fabfile.py

def new_app_instance():
    "Makes a new app instance with an EBS volume"
    # ... snip ...
    prepare_app_instance(instance.dns_name)
    return instance.id

def prepare_app_instance(hostname):
  "Prepares the given hostname to run chef"
  env.hosts        = [hostname]
  env.user         = "root"
  env.key_filename = config.key
  run("yum install -y make gcc rsync sudo openssl-devel rubygems ruby-devel ruby-shadow")
  run("gem install chef --no-ri --no-rdoc --source http://gems.opscode.com --source http://gems.rubyforge.org")