03 - EC2 SAA Level

EC2 SAA Level - Overview

awsec2saa-c03index

EC2 Solutions Architect Associate Level - Overview

Course Section Summary

This section covers advanced EC2 topics for the Solutions Architect Associate exam.

Study Files

# Topic File Priority
1 Private vs Public vs Elastic IP 01-Private-Public-Elastic-IP 🔴 High
2 EC2 Placement Groups 02-EC2-Placement-Groups 🔴 High
3 Elastic Network Interfaces (ENI) 03-Elastic-Network-Interfaces 🔴 High
4 EC2 Hibernate 04-EC2-Hibernate 🟡 Medium

Key Exam Topics

1. IP Addressing

  • Public IP: Globally unique, changes on stop/start
  • Private IP: VPC-internal, persists on stop/start
  • Elastic IP: Static public IP, $0.005/hour, limit 5/account
  • Best practice: Use DNS/Load Balancers instead of Elastic IPs

2. Placement Groups

Strategy Use Case Limit
Cluster HPC, low latency Single AZ, high risk
Spread Critical apps, HA 7 instances/AZ
Partition Hadoop, Kafka 7 partitions/AZ, 100s of instances

3. Elastic Network Interfaces

  • Virtual network card (private IP, security groups, MAC)
  • Bound to specific AZ
  • Can move between instances for failover
  • Manually created ENIs persist after instance termination

4. EC2 Hibernate

  • RAM saved to encrypted EBS root volume
  • Fast boot (OS not restarted)
  • Requirements: RAM < 150GB, encrypted EBS root
  • Max 60 days hibernation

Quick Reference

Placement Group Decision Tree

Need lowest latency?
├── Yes → Cluster (same rack, 10Gbps)
└── No
    ├── Need max availability (small scale)?
    │   └── Spread (7 per AZ, different hardware)
    └── Need scale + isolation?
        └── Partition (Hadoop, Kafka)

IP Behavior on Stop/Start

IP Type Changes?
Public IPv4 Yes (may change)
Private IPv4 No
Elastic IP No (static)

ENI Failover Pattern

1. Create secondary ENI with known IP
2. Attach to primary instance
3. On failure: Detach → Attach to standby
4. Same IP, different instance

Hands-On Checklist

  • Observe Public IP change on stop/start
  • Allocate and associate Elastic IP
  • Create all 3 placement group types
  • Create and move ENI between instances
  • Enable and test EC2 Hibernate (uptime command)

Check yourself

Quiz