Add extra information for AWS README

Make security group an environment variable with default to ‘public’

1 files changed, 20 insertions, 2 deletions

diff --git a/README_AWS.md b/README_AWS.md
index e877f34c6..37f4c5f51 100644
--- a/README_AWS.md
+++ b/README_AWS.md
@@ -14,7 +14,7 @@ Create a credentials file
    export AWS_ACCESS_KEY_ID='AKIASTUFF'
    export AWS_SECRET_ACCESS_KEY='STUFF'
 ```
-1. source this file
+2. source this file
 ```
   source ~/.aws_creds
 ```
@@ -23,7 +23,7 @@ Note: You must source this file in each shell that you want to run cloud.rb
 
 (Optional) Setup your $HOME/.ssh/config file
 -------------------------------------------
-In case of a cluster creation, or any other case where you don't know the machine hostname in advance, you can use '.ssh/config' 
+In case of a cluster creation, or any other case where you don't know the machine hostname in advance, you can use '.ssh/config'
 to setup a private key file to allow ansible to connect to the created hosts.
 
 To do so, add the the following entry to your $HOME/.ssh/config file and make it point to the private key file which allows you to login on AWS.
@@ -34,6 +34,24 @@ Host *.compute-1.amazonaws.com
 
 Alternatively, you can configure your ssh-agent to hold the credentials to connect to your AWS instances.
 
+(Optional) Choose where the cluster will be launched
+----------------------------------------------------
+
+By default, a cluster is launched with the following configuration:
+
+- Instance type: m3.large
+- AMI: ami-307b3658
+- Region: us-east-1
+- Keypair name: libra
+- Security group: public
+
+If needed, these values can be changed by setting environment variables on your system.
+
+- export ec2_instance_type='m3.large'
+- export ec2_ami='ami-307b3658'
+- export ec2_region='us-east-1'
+- export ec2_keypair='libra'
+- export ec2_security_group='public'
 
 Install Dependencies
 --------------------