Amazon Machine Images (AMI)

• This porved the information required to launch an ec2 instance. We can launch multiple ec2 instances using the same AMI
• Every AMI has a unique id. Two AMI which have exactly same images in different regions will have different ids.
• Snapshot: EBS snapshot is copy of the EBS Volume
• AMI:
  • Collection of one-more EBS snapshots, Block Device mapping which specfies the volumes attached when an instance is launched and Launch permissions
• AWS MarketPlace:
  • Third party ami’s can be purchased for AWS MarketPlace images
  • Market place amis might have software licening costs
• AWS Community AMI will not have Software licensing costs
• Lets create an Centos 7 instance from AWS Community AMIs t2.micro
• While deleting the EC2 instances for community amis/market place ami’s ensure you delete the ebs volumes
• We can create custom AMIs in AWS which will have our applications pre-installed.
• Scenario: Lets assume your organization is developing applications which require java 8 and tomcat 8. So lets create an AMI with java 8 & tomcat 8 pre installed.
  • Create an ec2 instance with any linux distribution (ubuntu 18)
  • Now login into ec2 instance and execute the following commands

  sudo apt update
  sudo apt install openjdk-8-jdk tomcat8 -y
  

  • Navigate to http://<public-ip>:8080/ and you should be able to see the tomcat’s welcome page
  • Now lets create a reusable AMI with tomcat8 pre-installed
  • Select the ami created and launch an ec2 instance (t2.micro)
• AWS AMI Virtualization Types
  • Linux AMIs use one of two virtualizations
    • Paravirtual (PV):
      • PV AMIs boot with a special boot loader called as PV-GRUB, starts the boot cycle and then chain loads the kernel specified in menu.lst file on your image.
    • Hardware Virtual Machine (HVM):
      • HVA AMIs are presented with a fully virtualized set of hardware and boot by execute Master Boot Record of the root block device of your image.
• Exercise:
  • Create a lamp stack ami on centos 7 Refer Here
  • Ensure AWS CLI is Installed Refer Here