Google Compute Engine provides virtual machines that you can use to run your own Cloud-hosted applications on the same infrastructure that runs all of Google. You can choose from a variety of virtual machines types that best fit your requirements and your budget.
Root access to your server. Usually VPS or dedicated servers comes with Root access. It will NOT work on share hosting without Root access. If unsure ask your host.
To install Open Atrium the first time, you will run the "install.php" script from your web browser. NOTE when using a hosting company such as Pantheon, it will run install.php for you. The Install script will take you through multiple pages of steps. There is very little difference between this process and a normal Drupal site installation except that it takes longer to install the large number of modules.
Amazon EC2 allows site administrators the ability to scale easily while maintaining manageable costs. Much like any other cloud service the service is a pay as you go service. You select the instance type. They offer various sizes: micro, small, medium, large, etc. The larger the instances the more resources you're provided. It comes at a greater cost. In order to figure out costs, amazon provides a Amazon Web Services calculator to figure out a monthly cost.
Creating an account / logging in
Create or Login to the Amazon Web Service Management Console.
Amazon offer many different services. Select Amazon EC2.
On the left hand side navigation, look for, "Instances" and click on it.
Configuring your instance
Select the Linux Amazon Machine Image (AMI) of your preference. (You Can select any but you may need to pay for some futures.)
Once you select through the options of your preferred Linux distribution, your instance shall launch.