EC2 basics

Question 1

What level of resilience does EC2 have?

Answer 1

Availability Zone Resilient - the instance fails if the AZ fails

Question 2

What cloud service model is EC2?

Answer 2

IAAS - infrastructure as a service

The unit of consumption is the instance. The user manages the OS (operating system) and upwards

Question 3

Is EC2 a private or public AWS service?

Answer 3

Private by default

Launches into a single VPC

Question 4

What are the states of an EC2 instance?

Answer 4

Provisioning - being created

Running - instance is running

Stopped - instance is not running

Terminated - instance is shutdown (not reversible)

Question 5

What are the transitions of the EC2 instance states?

Answer 5

Provisioning -> Running

Running -> Stopped

Stopped -> Running (instance restarted)

Stopped -> Terminated

Question 6

What states of the instance are billed?

Answer 6

Running:

• CPU
• Memory
• Disk (EBS)
• Memory

Stopped:
- Disk (EBS) only - storage is still allocated to the instance

Question 7

What is the purpose of EC2?

Answer 7

• Rent virtual machines (EC2)
• Store data on virtual drives (EBS)
• Distribute load across machines (ELB)
• Scale services using an auto-scaling group (ASG)

Question 8

What config options are available for EC2?

Answer 8

• OS
• CPU
• RAM
• Storage space (EBS & EFS, EC2 Instance Store)
• Network card (ENI?)
• Firewall Rules (security group)
• Bootstrap script (EC2 User Data)

Question 9

What is an EC2 User Data Script?

Answer 9

• A script that runs once when the instance is started
• Automates boot tasks
  
  • Install updates
  • Install Software
  • download common files from the internet