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

Recall & Review

beginner

What is the main goal of high availability design patterns?

To ensure that applications and services remain accessible and operational with minimal downtime, even during failures or maintenance.

intermediate

Explain the Active-Active pattern in high availability.

Active-Active means running multiple instances of a service simultaneously in different locations. Traffic is distributed among them, so if one fails, others keep working without interruption.

intermediate

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

Active-Active runs all instances at the same time sharing the load. Active-Passive runs one active instance and one or more standby instances that only start if the active one fails.

beginner

How does Azure Availability Zones help with high availability?

Availability Zones are separate physical locations within an Azure region. Deploying resources across zones protects against data center failures, improving uptime.

beginner

What role does load balancing play in high availability?

Load balancers distribute user traffic across multiple healthy instances, preventing overload and ensuring continuous service if some instances fail.

Which pattern runs multiple service instances simultaneously to share load and improve availability?

A Active-Active

B Active-Passive

C Single Instance

D Cold Standby

Active-Active runs multiple instances at the same time to share load and provide high availability.

What Azure feature provides physically separate locations within a region for fault tolerance?

A Virtual Networks

B Resource Groups

C Availability Zones

D Azure Functions

Availability Zones are separate physical locations in an Azure region to improve fault tolerance.

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

A Traffic stops until manual restart

B All instances shut down

C Load balancer ignores the failure

D The passive instance becomes active

The passive instance takes over to keep the service running.

Why is load balancing important for high availability?

A It distributes traffic to healthy instances

B It stores backup data

C It encrypts network traffic

D It creates virtual machines

Load balancers distribute traffic to prevent overload and handle failures.

Which of these is NOT a high availability design pattern?

A Active-Active

B Single Instance

C Active-Passive

D Multi-Region Deployment

Single Instance does not provide high availability because it has no redundancy.

Describe how you would design a highly available web application using Azure services.

Think about spreading resources and balancing traffic.

Explain the benefits and trade-offs between Active-Active and Active-Passive high availability patterns.

Consider cost, complexity, and downtime.