Vagrantfile updates.

- Remove the overrides config.vm.box and config.vm.box_url and use
  the same values for all providers.
- Use the same private key path for all providers.  It is still possible
  to set a different private key path through the environment variable
  SSH_PRIVKEY_PATH if desired (your AWS key may be different from your
  Virtualbox key).
- Allow the environment variable AWS_INSTANCE_TYPE to specify the
  instance type of instead of hard coding the AWS instance type as
  't1.micro'.  't1.micro' is still the default if unspecified.
- Use the same environment variables for keys as the Amazon provided EC2
  API tools.  This allows people who already have the EC2 tools set up
  correctly to use 'vagrant up' with less environment configuration
  than before.
- Rewrite the provisioning code.  The goal is to be idempotent and to
  correctly install docker for all providers instead of just virtualbox.
  It will conditionally install the virtualbox guest additions if
  virtualbox is the provider.
- Update the AWS install documentation to reflect the changes.

Vagrantfile

@@ -4,65 +4,135 @@
 BOX_NAME = ENV['BOX_NAME'] || "ubuntu"
 BOX_URI = ENV['BOX_URI'] || "http://files.vagrantup.com/precise64.box"
 VF_BOX_URI = ENV['BOX_URI'] || "http://files.vagrantup.com/precise64_vmware_fusion.box"
+AWS_BOX_URI = ENV['BOX_URI'] || "https://github.com/mitchellh/vagrant-aws/raw/master/dummy.box"
 AWS_REGION = ENV['AWS_REGION'] || "us-east-1"
-AWS_AMI    = ENV['AWS_AMI']    || "ami-d0f89fb9"
+AWS_AMI = ENV['AWS_AMI'] || "ami-69f5a900"
+AWS_INSTANCE_TYPE = ENV['AWS_INSTANCE_TYPE'] || 't1.micro'
+
 FORWARD_DOCKER_PORTS = ENV['FORWARD_DOCKER_PORTS']
 
+SSH_PRIVKEY_PATH = ENV["SSH_PRIVKEY_PATH"]
+
+# A script to upgrade from the 12.04 kernel to the raring backport kernel (3.8)
+# and install docker.
+$script = <<SCRIPT
+# The username to add to the docker group will be passed as the first argument
+# to the script.  If nothing is passed, default to "vagrant".
+user="$1"
+if [ -z "$user" ]; then
+    user=vagrant
+fi
+
+# Adding an apt gpg key is idempotent.
+wget -q -O - https://get.docker.io/gpg | apt-key add -
+
+# Creating the docker.list file is idempotent, but it may overrite desired
+# settings if it already exists.  This could be solved with md5sum but it
+# doesn't seem worth it.
+echo 'deb http://get.docker.io/ubuntu docker main' > \
+    /etc/apt/sources.list.d/docker.list
+
+# Update remote package metadata.  'apt-get update' is idempotent.
+apt-get update -q
+
+# Install docker.  'apt-get install' is idempotent.
+apt-get install -q -y lxc-docker
+
+usermod -a -G docker "$user"
+
+tmp=`mktemp -q` && {
+    # Only install the backport kernel, don't bother upgrade if the backport is
+    # already installed.  We want parse the output of apt so we need to save it
+    # with 'tee'.  NOTE: The installation of the kernel will trigger dkms to
+    # install vboxguest if needed.
+    apt-get install -q -y --no-upgrade linux-image-generic-lts-raring | \
+        tee "$tmp"
+
+    # Parse the number of installed packages from the output
+    NUM_INST=`awk '$2 == "upgraded," && $4 == "newly" { print $3 }' "$tmp"`
+    rm "$tmp"
+}
+
+# If the number of installed packages is greater than 0, we want to reboot (the
+# backport kernel was installed but is not running).
+if [ "$NUM_INST" -gt 0 ];
+then
+    echo "Rebooting down to activate new kernel."
+    echo "/vagrant will not be mounted.  Use 'vagrant halt' followed by"
+    echo "'vagrant up' to ensure /vagrant is mounted."
+    shutdown -r now
+fi
+SCRIPT
+
+# We need to install the virtualbox guest additions *before* we do the normal
+# docker installation.  As such this script is prepended to the common docker
+# install script above.  This allows the install of the backport kernel to
+# trigger dkms to build the virtualbox guest module install.
+$vbox_script = <<VBOX_SCRIPT + $script
+# Install the VirtualBox guest additions if they aren't already installed.
+if [ ! -d /opt/VBoxGuestAdditions-4.2.12/ ]; then
+    # Update remote package metadata.  'apt-get update' is idempotent.
+    apt-get update -q
+
+    # Kernel Headers and dkms are required to build the vbox guest kernel
+    # modules.
+    apt-get install -q -y linux-headers-generic-lts-raring dkms
+
+    echo 'Downloading VBox Guest Additions...'
+    wget -cq http://dlc.sun.com.edgesuite.net/virtualbox/4.2.12/VBoxGuestAdditions_4.2.12.iso
+
+    mount -o loop,ro /home/vagrant/VBoxGuestAdditions_4.2.12.iso /mnt
+    /mnt/VBoxLinuxAdditions.run --nox11
+    umount /mnt
+fi
+VBOX_SCRIPT
+
 Vagrant::Config.run do |config|
   # Setup virtual machine box. This VM configuration code is always executed.
   config.vm.box = BOX_NAME
   config.vm.box_url = BOX_URI
 
-  config.ssh.forward_agent = true
-
-  # Provision docker and new kernel if deployment was not done.
-  # It is assumed Vagrant can successfully launch the provider instance.
-  if Dir.glob("#{File.dirname(__FILE__)}/.vagrant/machines/default/*/id").empty?
-    # Add lxc-docker package
-    pkg_cmd = "wget -q -O - https://get.docker.io/gpg | apt-key add -;" \
-      "echo deb http://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list;" \
-      "apt-get update -qq; apt-get install -q -y --force-yes lxc-docker; "
-    # Add Ubuntu raring backported kernel
-    pkg_cmd << "apt-get update -qq; apt-get install -q -y linux-image-generic-lts-raring; "
-    # Add guest additions if local vbox VM. As virtualbox is the default provider,
-    # it is assumed it won't be explicitly stated.
-    if ENV["VAGRANT_DEFAULT_PROVIDER"].nil? && ARGV.none? { |arg| arg.downcase.start_with?("--provider") }
-      pkg_cmd << "apt-get install -q -y linux-headers-generic-lts-raring dkms; " \
-        "echo 'Downloading VBox Guest Additions...'; " \
-        "wget -q http://dlc.sun.com.edgesuite.net/virtualbox/4.2.12/VBoxGuestAdditions_4.2.12.iso; "
-      # Prepare the VM to add guest additions after reboot
-      pkg_cmd << "echo -e 'mount -o loop,ro /home/vagrant/VBoxGuestAdditions_4.2.12.iso /mnt\n" \
-        "echo yes | /mnt/VBoxLinuxAdditions.run\numount /mnt\n" \
-          "rm /root/guest_additions.sh; ' > /root/guest_additions.sh; " \
-        "chmod 700 /root/guest_additions.sh; " \
-        "sed -i -E 's#^exit 0#[ -x /root/guest_additions.sh ] \\&\\& /root/guest_additions.sh#' /etc/rc.local; " \
-        "echo 'Installation of VBox Guest Additions is proceeding in the background.'; " \
-        "echo '\"vagrant reload\" can be used in about 2 minutes to activate the new guest additions.'; "
-    end
-    # Add vagrant user to the docker group
-    pkg_cmd << "usermod -a -G docker vagrant; "
-    # Activate new kernel
-    pkg_cmd << "shutdown -r +1; "
-    config.vm.provision :shell, :inline => pkg_cmd
+  # Use the specified private key path if it is specified and not empty.
+  if SSH_PRIVKEY_PATH
+      config.ssh.private_key_path = SSH_PRIVKEY_PATH
   end
-end
 
+  config.ssh.forward_agent = true
+end
 
 # Providers were added on Vagrant >= 1.1.0
+#
+# NOTE: The vagrant "vm.provision" appends its arguments to a list and executes
+# them in order.  If you invoke "vm.provision :shell, :inline => $script"
+# twice then vagrant will run the script two times.  Unfortunately when you use
+# providers and the override argument to set up provisioners (like the vbox
+# guest extensions) they 1) don't replace the other provisioners (they append
+# to the end of the list) and 2) you can't control the order the provisioners
+# are executed (you can only append to the list).  If you want the virtualbox
+# only script to run before the other script, you have to jump through a lot of
+# hoops.
+#
+# Here is my only repeatable solution: make one script that is common ($script)
+# and another script that is the virtual box guest *prepended* to the common
+# script.  Only ever use "vm.provision" *one time* per provider.  That means
+# every single provider has an override, and every single one configures
+# "vm.provision".  Much saddness, but such is life.
 Vagrant::VERSION >= "1.1.0" and Vagrant.configure("2") do |config|
   config.vm.provider :aws do |aws, override|
-    aws.access_key_id = ENV["AWS_ACCESS_KEY_ID"]
-    aws.secret_access_key = ENV["AWS_SECRET_ACCESS_KEY"]
+    username = "ubuntu"
+    override.vm.box_url = AWS_BOX_URI
+    override.vm.provision :shell, :inline => $script, :args => username
+    aws.access_key_id = ENV["AWS_ACCESS_KEY"]
+    aws.secret_access_key = ENV["AWS_SECRET_KEY"]
     aws.keypair_name = ENV["AWS_KEYPAIR_NAME"]
-    override.ssh.private_key_path = ENV["AWS_SSH_PRIVKEY"]
-    override.ssh.username = "ubuntu"
+    override.ssh.username = username
     aws.region = AWS_REGION
     aws.ami    = AWS_AMI
-    aws.instance_type = "t1.micro"
+    aws.instance_type = AWS_INSTANCE_TYPE
   end
 
-  config.vm.provider :rackspace do |rs|
-    config.ssh.private_key_path = ENV["RS_PRIVATE_KEY"]
+  config.vm.provider :rackspace do |rs, override|
+    override.vm.provision :shell, :inline => $script
     rs.username = ENV["RS_USERNAME"]
     rs.api_key  = ENV["RS_API_KEY"]
     rs.public_key_path = ENV["RS_PUBLIC_KEY"]
@@ -71,20 +141,25 @@ Vagrant::VERSION >= "1.1.0" and Vagrant.configure("2") do |config|
   end
 
   config.vm.provider :vmware_fusion do |f, override|
-    override.vm.box = BOX_NAME
     override.vm.box_url = VF_BOX_URI
     override.vm.synced_folder ".", "/vagrant", disabled: true
+    override.vm.provision :shell, :inline => $script
     f.vmx["displayName"] = "docker"
   end
 
-  config.vm.provider :virtualbox do |vb|
-    config.vm.box = BOX_NAME
-    config.vm.box_url = BOX_URI
+  config.vm.provider :virtualbox do |vb, override|
+    override.vm.provision :shell, :inline => $vbox_script
     vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
     vb.customize ["modifyvm", :id, "--natdnsproxy1", "on"]
   end
 end
 
+# If this is a version 1 config, virtualbox is the only option.  A version 2
+# config would have already been set in the above provider section.
+Vagrant::VERSION < "1.1.0" and Vagrant::Config.run do |config|
+  config.vm.provision :shell, :inline => $vbox_script
+end
+
 if !FORWARD_DOCKER_PORTS.nil?
   Vagrant::VERSION < "1.1.0" and Vagrant::Config.run do |config|
     (49000..49900).each do |port|

docs/sources/installation/amazon.rst

@@ -102,26 +102,45 @@ Docker that way too. Vagrant 1.1 or higher is required.
    we need to set them there first. Make sure you have everything on
    amazon aws setup so you can (manually) deploy a new image to EC2.
 
+   Note that where possible these variables are the same as those honored by
+   the ec2 api tools.
    ::
 
-       export AWS_ACCESS_KEY_ID=xxx
-       export AWS_SECRET_ACCESS_KEY=xxx
+       export AWS_ACCESS_KEY=xxx
+       export AWS_SECRET_KEY=xxx
        export AWS_KEYPAIR_NAME=xxx
-       export AWS_SSH_PRIVKEY=xxx
+       export SSH_PRIVKEY_PATH=xxx
 
-   The environment variables are:
+       export BOX_NAME=xxx
+       export AWS_REGION=xxx
+       export AWS_AMI=xxx
+       export AWS_INSTANCE_TYPE=xxx
 
-   * ``AWS_ACCESS_KEY_ID`` - The API key used to make requests to AWS
-   * ``AWS_SECRET_ACCESS_KEY`` - The secret key to make AWS API requests
+   The required environment variables are:
+
+   * ``AWS_ACCESS_KEY`` - The API key used to make requests to AWS
+   * ``AWS_SECRET_KEY`` - The secret key to make AWS API requests
    * ``AWS_KEYPAIR_NAME`` - The name of the keypair used for this EC2 instance
-   * ``AWS_SSH_PRIVKEY`` - The path to the private key for the named
+   * ``SSH_PRIVKEY_PATH`` - The path to the private key for the named
      keypair, for example ``~/.ssh/docker.pem``
 
+   There are a number of optional environment variables:
+
+   * ``BOX_NAME`` - The name of the vagrant box to use.  Defaults to
+     ``ubuntu``.
+   * ``AWS_REGION`` - The aws region to spawn the vm in.  Defaults to
+     ``us-east-1``.
+   * ``AWS_AMI`` - The aws AMI to start with as a base.  This must be
+     be an ubuntu 12.04 precise image.  You must change this value if
+     ``AWS_REGION`` is set to a value other than ``us-east-1``.
+     This is because AMIs are region specific.  Defaults to ``ami-69f5a900``.
+   * ``AWS_INSTANCE_TYPE`` - The aws instance type.  Defaults to ``t1.micro``.
+
    You can check if they are set correctly by doing something like
 
    ::
 
-      echo $AWS_ACCESS_KEY_ID
+      echo $AWS_ACCESS_KEY
 
 6. Do the magic!