• Basic compute solution for AWS. runtimes, OS’s
• IAAS, gives you access to instances. you manage from the OS upwards
• Private service by default
• Uses VPC networking
• AZ resilient. Instance fails if AZ fails
• Can use local on-host storage, or Elastic Block Store (Network storage)
• EC2 has a soft limit of 20 instances per region

Instance lifecycle

• Running - using CPU, memory, network, & storage
• Stopped - no CPU, memory, or network resources being used. Only storage
• Terminated - can’t reverse this.
• can go from running to stopped & vice versa

Instance types

• On demand
• Reserved - these have a time commitment. gives 30-70% discount. Various payment options - no upfront, all upfront, partial upfront
• Spot - cheap, meant for short lived instances, few hours to a few days. they use bid pricing
• Dedicated - not sharing memory/cpu

Amazon Machine Image (AMI)

Connecting to EC2

• Windows uses RDP - Port 3389
• Linux uses SSH - Port 22 - using key pairs

Auto scaling groups

• They use launch configurations, these specify the usual EC2 launch stuff.

  • AMI + instance type
  • EC2 user data
  • EBS volumes
  • Security Groups
  • SSH keypair

• ASG is usually put behind a load balancer

• Can scale based on:

  • cloudwatch alarms
  • target average CPU usage
  • number of requests on the ELB per instance
  • average network in
  • average network out
  • custom metric, such as number of users connected to application

Storage

• EFS - file level storage service, that can provide a shared file system
• EBS - virtual hard disk. 1 EC2 -> 1 EBS
• EFS vs EBS
• Elasticache - managed caching service for Memcached & redis