High availability design patterns in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main goal of high availability design patterns?

To ensure that a system or service remains operational and accessible with minimal downtime, even during failures or maintenance.

intermediate

Explain the concept of 'Active-Active' high availability pattern.

In Active-Active, multiple instances of a service run simultaneously in different locations. Traffic is distributed among them, so if one fails, others continue serving without interruption.

intermediate

What is the difference between 'Active-Passive' and 'Active-Active' patterns?

Active-Passive has one active instance and one or more standby instances that take over if the active fails. Active-Active runs all instances actively and shares the load.

beginner

How does AWS Elastic Load Balancer (ELB) support high availability?

ELB distributes incoming traffic across multiple healthy instances in different Availability Zones, helping maintain service availability if some instances fail.

beginner

Why is multi-AZ deployment important for high availability in AWS?

Multi-AZ deployment places resources in different physical locations (Availability Zones) to protect against data center failures, ensuring the system stays available.

Which pattern involves multiple active instances serving traffic simultaneously?

A Cold Standby

B Active-Passive

C Active-Active

D Single Instance

Active-Active means all instances are active and share the load.

What AWS service helps distribute traffic to multiple instances for high availability?

A Amazon S3

B AWS Lambda

C Amazon RDS

D Elastic Load Balancer (ELB)

ELB balances traffic across healthy instances to maintain availability.

Why deploy resources in multiple Availability Zones (AZs)?

A To protect against data center failures

B To improve security

C To reduce costs

D To increase latency

Multi-AZ deployment protects against failures in one data center.

In an Active-Passive pattern, what happens when the active instance fails?

A The passive instance takes over

B The system shuts down

C Traffic is lost

D Both instances fail

The passive instance becomes active to keep the system running.

Which of these is NOT a benefit of high availability design patterns?

A Reduced downtime

B Increased single point of failure

C Improved fault tolerance

D Better user experience

High availability patterns reduce single points of failure, not increase them.

Describe the Active-Active and Active-Passive high availability patterns and when you might use each.

Think about how many instances run at the same time and how traffic is handled.

Explain why deploying resources across multiple Availability Zones improves system availability in AWS.

Consider what happens if one data center goes down.