Virtual Machines in AWS

• Called as EC2

Dependencies for EC2 instances on other AWS Services

• Network:
  • All aws ec2 instances belong to some subnet in VPC.
  • By default they get created in Default VPC
  • Security Group: just think of it as a firewall
• Storage:
  • What is type of hard disk which you want to use
  • Types:
    • Instance Store
    • EBS

Other Things in EC2 to be considered

• AMI (Amazon Machine Image):
  • Which OS has to be used to create EC2 instance
  • Three kinds of AMIs
    • AWS Managed:
      • Managed by AWS with basic OS images and some extra softwares
    • Market Place:
      • Images created by Third Parties.
      • Extra licensing costs can be imposed
    • Custom Images:
      • Images created by users.
      • Generally will have your applications preconfigured.
• KeyPair:
  • AWS by default disables password authentication.
  • Keypair RSA based Private and Public keys
  • Can be created in AWS or Create them in your servers and import the public key to AWS.
• Instance Type:
  • number of Cpus
  • Size of RAM
  • Network Speed
  • Kind of Hardware
  • Number of Instance Stores

Diagnostic Information about EC2 machines

• System Log:
  • Instance Settings => Get System Log
• Instane Screen Shot:
  • Instance Settings => Get Instance ScreenShot
• How to Change Instance Type of the EC2 Instance:
  • Shutdown the EC2 instance
  • Instance Settings => Change Instance Type
  • Note: requires downtime.

Instance States

• running
• stopped
• terminated => Deleted
• Reboot

Attaching Roles

• Roles can be attached and changed when ec2 machine is running.

Execute Some Script Once the EC2 machine is created

• User-Data