AMI 101

Question 1

What does AMI stand for?

Answer 1

Amazon Machine Image

Question 2

What is an AMI?

Answer 2

A template that contains a software configuration.

Question 3

What is an instance?

Answer 3

• An instance is a virtual server in the cloud
• It’s configuration at launch is a copy of the AMI that you specified when you launched the instance.

Question 4

What are the attributes based on which you can select an AMI?

Answer 4

• Region
• OS
• Architecture
• Launch Permissions
• Storage for the Root Device (Root Device Volume)

Question 5

What is a root device?

Answer 5

• When you launch an instance, the root device volume contains the image used to boot the instance.
• Think of it as where the OS is installed

Question 6

What are the two types of Root Device Volumes for AMIs?

Answer 6

1. Instance Store
2. EBS-backed volumes

Question 7

What are the key differences between the two types of root device volumes for AMIs?

Answer 7

• In an EBS-backed volume, the Root Device is an EBS volume created from an EBS snapshot
• In an Instance Store Volume, the Root Device is an instance store volume created from a template stored in S3

Question 8

Why are Instance Store Volumes sometimes also called Ephemeral Volumes?

Answer 8

Instance Store volumes cannot be stopped. If the underlying host fails, you lose the data.

(EBS-backed instancess CAN be stopped, and you do NOT lose the data if it is stopped)

Question 9

If you reboot a Root Device volume, do you lose your data?

Answer 9

No

Question 10

By default, When you terminate a root device volume, is the volume deleted?

Answer 10

Yes, but for EBS volumes, you can tell AWS to keep the root device volume