I am asked often about the ins and outs of Amazon Web Services – Buy Aws Account by C-levels, directors and managers. They aren’t looking for nitty gritty nuances of scripting with the API of the Elastic Compute Cloud, they are just interested in the general overview of how the ‘cloud’ works.
When explaining AWS for the first time to managers (or anyone, for that matter) it is best to talk in concepts rather than in concrete terms. I’ve also noticed it is beneficial to try to tangiblize the discussion with familiar terms. Using terms like “Elastic IP” gets quizical looks, but calling it a publicly accessible IP address helps people to get a better overall grasp of concepts before using the AWS terms for things.
At a very high level, you can think of EC2 as a global computing environment. Within EC2 are geographical regions that can thought of as data centers. Inside of these data centers are computer clusters that in AWS parlance are call Availability Zones:
– EC2 (think: cloud)
—— Regions (think: data center)
————- Availability Zones (think: computer cluster)
Inside of an Availability Zone, we have can create virtual machines from predefined or custom Amazon Machine Images, or AMIs. An AMI can thought of as a snapshot of machine that you can load and run inside the cloud at an Availability Zone. Each time you take an AMI and start it, it is call an Instance of the AMI. You can take an AMI and start it several times, each time creates a new Instance.
Instances are virtual machines that are running, and I really mean they are virtual. If precautions are not taken, these virtual machines can wink out of existence and cause a great deal of consternation. So you don’t really want to think of an Instance as something that is robust and persistent. It is merely a unit of computational resources.
Virtual Hard Drives
To help keep your data intact even when an Instance dies. You can use several different AWS services but one of the more common ones is the Elastic Block Store, or EBS. Think of EBS as a hard drive. You can make an EBS from 1GB to 1TB and ‘install’ it on any of your virtual machine Instances. So, if you have an Instance that is running your website and you want to make sure the database stays healthy even if the Instance disappears, you can use an EBS ‘hard drive’. In the vernacular of AWS, you have created an EBS volume and mounted it on an Instance.