AWS Solutions Architect Quiz 3 🎓 (CloudFront, ElastiCache)
Published: 2021-03-15 14:59:50

The AWS solutions architect certification shows that you can use AWS services to solve software engineering problems and understand core best practices of the industry. In this article, I will quiz you on two sections from the material required for the exam: CloudFront, ElastiCache.

![](https://cdn-images-1.medium.com/max/2800/1*p4U3M2JgXaMfaKLlFRAIYA.png)

I will now briefly state some key facts about each AWS service, and then provide some example questions for the exam.

N.B: The following information on its own will not be enough to answer the questions.

### [CloudFront](https://aws.amazon.com/cloudfront/)

The CloudFront service is a global Content Delivery Network (CDN) service which allows users to distribute data with low latency and high transfer speeds.

![CloudFront Distribution Map — [https://aws.amazon.com/cloudfront/features/](https://aws.amazon.com/cloudfront/features/)](https://cdn-images-1.medium.com/max/3312/1*WhX2WcZhgmbnelGmjA74ew.png)*

CloudFront Distribution Map — [https://aws.amazon.com/cloudfront/features/](https://aws.amazon.com/cloudfront/features/)*

It is also useful to know:

* AWS CloudFront has 220+ Points of Presence (210+ Edge Locations and 12 Regional Edge Caches) in 87 cities across 44 countries.

* Collections of files/sources are called *Distributions.*

* Distributions can contain static files (HTML, JS, Audio, Video) and media streaming with valid origins of S3, EC2, ELB.

* Distributions are accessed via a DNS name which can be ALIAS in Route53.

* The CloudFront service uses DNS geo-location to serve content from closest edge location. If the content is not in the closest loation CloudFront fetches it from the origin server eg. S3.

* The default cache expire time is 24hrs — this can be set using cache control headers or TTL.

* Content can be evicted from an edge location (make room for more frequently requested content).

* CloudFront offers an Invalidate API which enables users to invalidate based on patterns e.g. `*.html` .

* Restrict access using signed urls, signed cookies, origin access Identities (OAI — special cloudfront users).

### [ElastiCache](https://aws.amazon.com/elasticache/)

The ElastiCache service is a managed scalable cache using the Memcached or Redis engines.

![Example ElastiCache Redis Cluster Architecture from [https://www.iteanz.com/tutorials/aws/amazon-elasticache/](https://www.iteanz.com/tutorials/aws/amazon-elasticache/)](https://cdn-images-1.medium.com/max/2000/1*hSSzzAZ4FEOvv6bSSY3IOw.jpeg)*

Example ElastiCache Redis Cluster Architecture from [https://www.iteanz.com/tutorials/aws/amazon-elasticache/](https://www.iteanz.com/tutorials/aws/amazon-elasticache/)*

It is also useful to know:

* Memcached clusters can contain up to 20 nodes and perform auto discovery meaning there is no need to describe the topology in infrastructure.

* A Redis cluster always contains a single node — clusters can be grouped in Redis replication group with a max of 5 read replicas.

* ElastiCache is able to detect node failure and provision replacements in the cluster. There is a heavy load on your DB while the queries are performed to refill the cache.

* If Redis Multi-AZ replication group is enabled a Read-Replica can be automatically promoted to being a primary node. Read replication is asynchronous.

* Vertical Scaling an ElastiCache cluster requires users to spin up a new cluster of different instance size and redirect traffic.

* A Redis snapshot is a full clone of data at a certain point of time and can be stored on S3.

* Access to ElastiCache cluster can be deployed into VPC and access controlled with security groups.

## Quiz 🎓



The quiz can also be accessed in full size [here](https://docs.google.com/forms/d/e/1FAIpQLSfWpXfj56I3LoLSCbo3q_Hfo4a_hY4cVp5no1_qrVA0SkSAFA/viewform). These questions were sourced from multiple locations (mainly the [certification sample test](https://d1.awsstatic.com/training-and-certification/docs-sa-assoc/AWS-Certified-Solutions-Architect-Associate_Sample-Questions_v4.0_FINAL.pdf)) over a long period of time.

## Thanks For Reading

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We hope to cover the rest of the topics with similar articles very soon ⭐

### **Quiz 1**
[**AWS Solutions Architect Quiz 🎓(VPC, Load balancing, CloudWatch Autoscaling)
**T*he AWS solutions architect certification shows that you can use AWS services to solve software engineering problems…m*edium.com](https://medium.com/@t3chflicks/aws-solutions-architect-quiz-vpc-load-balancing-cloudwatch-autoscaling-aa3edee34d16)

### **Quiz 2**
[**AWS Solutions Architect Quiz 2 🎓 (S3, EC2, EBS)
**T*he AWS solutions architect certification shows that you can use AWS services to solve software engineering problems…m*edium.com](https://medium.com/@t3chflicks/aws-solutions-architect-quiz-2-s3-ec2-ebs-173d40515dd)

### **Quiz 4**
[**AWS Solutions Architect Quiz 4🎓 (SQS, SNS)
**T*he AWS solutions architect certification shows that you can use AWS services to solve software engineering problems…m*edium.com](https://medium.com/@t3chflicks/aws-solutions-architect-quiz-4-sqs-sns-b0b4390d5475)

### Quiz 5
[**AWS Solutions Architect Quiz 5 🎓 (DNS and Route53)
**T*he AWS solutions architect certification shows that you can use AWS services to solve software engineering problems…t*3chflicks.medium.com](https://t3chflicks.medium.com/aws-solutions-architect-quiz-5-dns-and-route53-1ca28cf9c5a1)

### Quiz 6
[**AWS Solutions Architect Quiz 6 🎓 (IAM)
**T*he AWS solutions architect certification shows that you can use AWS services to solve software engineering problems…t*3chflicks.medium.com](https://t3chflicks.medium.com/aws-solutions-architect-quiz-6-iam-5d34116f3c73)