Provision & Automate free Amazon EC2 instances with Hosted Chef

1. Sign-Up with Amazon via this link and they will offer one year of usage (micro instance) to help you understand and evaluate EC2. Read their terms of usage carefully and make sure to only provision the free instances if you don't want to get dinged on costs due to ignorance or carelessness on your own part.
2. Now the free instance image provided by Amazon happens to run RHEL4 but the out-of-the-box Chef-Client requires a higher version of that OS! Luckily some, if not all, of the very same issues have already been tackled in a post on the opscode's help website. And here's a gist of my experience with it as well. In case it is difficult to follow, let me highlight the fact that the modified file that allows you to properly finish the chef-client installation process on the AWS image for Linux was found here: CHEF-2515
3. Some Notes:
   • Either command works well:
     • knife ec2 server create -x ec2-user -i /Users/xxx/.ec2/ec2.pem --template-file ~/chef-repo/.chef/bootstrap/centos5-gems-modified.erb
     • knife ec2 server create --ssh-user ec2-user -i ~/.ec2/ec2.pem -d centos5-gems-modified
   • I find it crucial to configure the appropriate Amazon security group as part of the instance creation otherwise its ends up using the "default" group. To do this, add it to your "knife ec2 server create" command with "-G groupName" and remember that it can be a comma separated list of security groups "-G secGroup1,secGroup2" if you want. Example:
     • knife ec2 server create --ssh-user ec2-user -i ~/.ec2/ec2.pem -d centos5-gems-modified -G elasticsearch