Select the region based on the

• Region or AZ
• OS
• Architecture (32 vs 64)
• Launch Permissions ?

Storage for root device

• Instance Store aka Ephemeral Storage
• EBS backed volumes

When selecting an AMI, the default will display

• Root device type = EBS

Community AMIs

• Instance Store are stored on S3
• You can attach Instance Store volumes at provisioning, but not later.
• Can attach EBS at any time

Instance Store VMs

• Can only reboot or terminate
• You cannot stop these!
• If there are issues, too bad.  You cannot stop and restart the VM to another hypervisor and will likely lose your VM

Exam Tips

• All AMIs are backed by EBS or Instance Store volumes
  • For EBS Volumes, the root device for an instance launched from the AMI is an EBS volume created from an Amazon EBS snapshot.
  • Fore Instance Store volumes, the root device for an instance launched from the AMI is an instance store volume created from a template stored in S3
    • As such, these take longer to provision.
• Instance Store is also known as Ephemeral Storage
• Instance Store volumes cannot be stopped.  If they have issues, or if the Hypervisor fails, you will likely lose your VM and your data (unless most data is stored on EBS 🙂
  • EBS Volumes CAN be stopped without any loss of data.
• You can REBOOT an Instance Store volume without loss of data
• By default, Instance Store volumes re deleted upon VM Termination.
  • EBS volumes can be kept.