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EC2

March 20, 2025

EC2 - Elastic Compute Cloud

Busy day, so not much progress, but here’s today’s summary about EC2.

What is EC2?

EC2 is one of the most popular AWS offerings.
EC2 = Elastic Compute Cloud = Infrastructure as a Service (IaaS).

It mainly consists of the capability to:

  • Rent virtual machines (EC2).
  • Store data on virtual drives (EBS).
  • Distribute load across machines (ELB).
  • Scale services using an Auto-Scaling Group (ASG).

EC2 Sizing & Configuration Options

When launching an EC2 instance, we can configure:

  • Operating System (OS): Linux, Windows, or macOS.
  • Compute power & cores: Number of vCPUs.
  • Memory: Amount of RAM.
  • Storage:
    • Network-attached: EBS & EFS.
    • Hardware storage: EC2 Instance Store.
  • Network card: Speed, public IP address.
  • Firewall rules: Managed via Security Groups.
  • Bootstrap script: Configure at first launch using EC2 User Data.

EC2 User Data

It’s possible to bootstrap EC2 instances using an EC2 User Data script.
Bootstrapping means launching commands when a machine starts.

  • The script runs only once, at the instance's first start.
  • EC2 User Data is used to automate boot tasks such as:
    • Installing updates.
    • Installing software.
    • Downloading common files from the internet.
    • Any other initialization task.
  • The script runs as root by default.