AMI 101 Flashcards
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instances-and-amis.html
What does AMI stand for?
Amazon Machine Image
What is an AMI?
A template that contains a software configuration.
What is an instance?
- 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.
What are the attributes based on which you can select an AMI?
- Region
- OS
- Architecture
- Launch Permissions
- Storage for the Root Device (Root Device Volume)
What is a root device?
- 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
What are the two types of Root Device Volumes for AMIs?
- Instance Store
- EBS-backed volumes
What are the key differences between the two types of root device volumes for AMIs?
- 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
Why are Instance Store Volumes sometimes also called Ephemeral Volumes?
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)
If you reboot a Root Device volume, do you lose your data?
No
By default, When you terminate a root device volume, is the volume deleted?
Yes, but for EBS volumes, you can tell AWS to keep the root device volume