AWS Resiliency

Question 1

What is resiliency?

Answer 1

The ability to recover when stressed by loads, attacks, or failure of any workload components.

Question 2

What is the difference between vertical and horizontal scaling?

What is the cost optimization for each?

Answer 2

Vertical scaling: Increasing the size of the instances.

Horizontal scaling: Increasing the amount of instances.

Cost optimization:

Question 3

What is elasticity?

Answer 3

Using automatic scaling alongside horizontal scaling to match capacity with demand.

Question 4

What can AWS Auto scaling do? What about EC2 Auto scaling?

What are the difference EC2 Auto scaling policies?

Question 5

Amazon Elastic Compute Cloud (EC2)

Question 6

Elastic Container Service (ECS)

Question 7

Elastic Kubernetes Service (EKS)

Question 8

AWS Lambda

Question 9

Relational Database Service (RDS)

Question 10

DynamoDB

Answer 10

NoSQL, low latency at extreme scale.

Question 11

Amazon Aurora

Answer 11

Cloud-native relational database service.

Question 12

Amazon Redshift

Answer 12

Data warehouse.

Question 13

For resiliency in RDS, when would you use read-replicas or a multi-AZ design?

Answer 13

Use read replicas for performance and availability benefis. (This is not a cache replacement.)

Multi-AZ design doesn’t scale your needs, allow you to access it directly, or provide added performance on the standby copy. Multi-AZ is only good for high availability.

Question 14

Which services provide caching abilities?

Answer 14

1. Amazon CloudFront
2. ElastiCache
3. DynamoDB Accelerator (DAX)

Question 15

What is RDS Proxy?

How does it make applications more scalable, resilient, and secure?

Answer 15

Gives applications the ability to pull and share database connections. This improves efficiency and app scalability.

Question 16

What are the AWS edge networking services?

When should you use each one?

Answer 16

1. Amazon CloudFront
2. Route 53
3. AWS Global Accelerator

Question 17

AWS Transfer Family

Answer 17

Grants the ability to create, automate, and monitor your file transfer and data processing.

Does not require your own code or infrastructure. Supports up to three AZs.

Question 18

What is service-oriented architecture? What is microservices architecture?

Answer 18

Service-oriented architecture:Making software components reusable through service interfaces

Microservices architecture: Makes software components smaller and simpler.

Question 19

What is the difference between API-driven, event-driven, and streaming data?

Question 20

Amazon API Gateway

Question 21

AWS Fargate

Answer 21

Serverless compute for containers.

Question 22

What is concurrency and transactions in AWS Lambda?

Question 23

Amazon Simple Queue Service (SQS)

Answer 23

definition…

Can deliver high throughput by scaling message producers and consumers horizontally.

Question 24

What is synchronous vs asynchronous decoupling?

Answer 24

Synchronous decoupling requires components to always be available.

Asynchronous decoupling involves communication between components through durable components.

Question 25

What is the difference between high availability and fault tolerance?

Answer 25

**High availability** is designing for minimal downtime. **Fault tolerance** is designing for *zero* downtime and is typically more expensive.

Question 26

What are ways to design an architecture for disaster recovery?

Answer 26

1. Backups stored offsite 2. Backups stored in the cloud 3. Run disaster simulation tests 4. Build resources needed for operational redundancy (like servers and databases)

Question 27

What are legacy applications?

Answer 27

Answer… Component migrations are not possible.

Question 28

What are the two disaster recovery objectives and their definitions?

Answer 28

1. **Recovery Time Objective (RTO):** Maximum acceptable delay between a service interruption and service restoration. *What's the maximum time the application can be unavailable?* 2. **Recovery Point Objective (RPO):** Maximum acceptable amount of time since the last data recovery point. *How often does the data need to be backed up?*

Question 29

What are the four disaster recovery strategies? | Which are active/active and active/passive? What's the RPO and RTO?

Answer 29

*Active/Active* * **Multi-site active-active:** Zero downtime and near zero data loss. $$$$. Real-time RTO/RPO. *Active/Passive* * **Warm Standby:** Smaller, always-running instance, with scalability available after event. $$$. Minutes of RTO/RPO. * **Pilot Light:** Data live, services idle. $$. 10s of minutes of RTO/RPO. * **Backup & Restore:** Provision all AWS resources and restore backups after event. $. Hours of RTO/RPO.

Question 30

How does Amazon Aurora work for cross-regional failover? | How long does it take to failover?

Question 31

How does RDS multi-AZ deployment failover work? | How long is the database down?

Question 32

How do DynamoDB global tables work? | What backup and recovery options does it have?

Question 33

How can you improve availability and disaster recovery for legacy applications that are not cloud native?

Question 34

AWS Elastic Disaster Recovery | How can it be used with on-premises and cloud-based applications?

Question 35

Amazon Machine Images (AMIs)

Question 36

EC2 Image Builder

Question 37

How do routing tables work?

Question 38

VPC Peering Connections

Question 39

AWS Transit Gateway

Question 40

AWS Site-to-Site VPN

Question 41

AWS Direct Connect Locations

Question 42

AWS Direct Connect Gateways

Question 43

AWS Route 53 Resolver

Question 44

Which services can automate deployment? | Which can be used for containers?

Answer 44

1. Elastic Beanstalk 2. CloudFormation 3. OpsWorks For containers: 1. ECS 2. EKS

Question 45

Which services can help you find vulnerabilities in your infrastructure and code?

Answer 45

1. Amazon Inspector 2. Amazon CodeGuru

Question 46

What are the various DNS routing capabilities of Route 53? | Which support global architectures?

Question 47

Amazon CloudWatch | How do you initate automated actions using CloudWatch alarms?

Question 48

AWS X-Ray

Question 49

EventBridge

Question 50

Amazon Polly | What is a use case for Polly in high availability and fault tolerance?

Answer 50

| Large volumes of IT service requests

Question 51

Which two services can be used to create a self-healing environment that can tolerate a single point of failure of a single EC2 instance, or a loss of an entire AZ?

Answer 51

| Is it EC2 Auto Scaling and Elastic Load Balancer?

Question 52

AWS Global Accelerator

Question 53

What's the difference between EC2 Auto Scaling and AWS Auto Scaling?

Question 54

What's the difference between stateful and stateless applications?

Question 55

What is a sticky session, and why does it keep customers on the same instance?