The Lifecycle of EC2 Instances

Amazon EC2 has several features and services. It provides to facilitate the management of Amazon EC2 instances over their entire lifecycle.

When instances launching:

There are several additional services and features that are useful when launching new Amazon EC2 instances.

Bootstrapping and User-data/Meta-Data:

 

Bootstrapping:

 

  • Refers to a self-starting process or set of commands without external input.
  • A great benefit of the cloud is the ability to script virtual hardware management in a manner that is not possible with on-premises hardware.
  • In order to realize the value of this, there has to be some way to configure instances and install applications programmatically when an instance is launched. The process of providing code to be run on an instance at launch is called bootstrapping.
  • On Linux instances this can be shell script, and on windows instances this can be a batch style script or a PowerShell script.

This Script can perform tasks such as:

  • Applying patches and updates to the OS
  • Enrolling in a directory service
  • Installing application software
  • Copying a longer script or program from storage to be run on the instances
  • Installing Chef or Puppet and assigning the instance a role so the configuration management software can configure the instance.
  • With EC2, we can bootstrap the instance (during the creation process) with custom commands (such as installing software packages, running updates, and configuring other various settings)

Viewing User-Data and Instance Meta-Data:

User-Data:

A step/section during the EC2 instance creation process where you can include your own custom commands via a script (i.e a bash script)

Here is an example of a bash script that automates the process of updating the yum package installer, install Apache Web Server, and start the Apache service.

 

 

Imp:- User-Data is stored with the instance and is not encrypted, so it is important to not include any secrets such as passwords or keys in the User-Data.

Meta-data:

When logged into an EC2 instance, you can view the instance user-data used during creation, or meta-data by the executing one of the following commands:

 

Curl http://169.254.169.254/latest/user-data                                    display bootstrapping commands

Curl http://169.254.169.254/latest/meta-data                                  display AMI, instance type, etc

Post Author: Rohit

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