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AWS concepts from A to Z

helenanders26 profile image Helen Anderson Updated on ・11 min read

There are a LOT of AWS services to get to grips with. Inspired by AWS in Plain English, I've created my own glossary of terminology to make sure I know my CloudFront from CloudTrail and Athena from Aurora.


DB Snapshot
Edge Location
Hosted Zone
Instance Type
Job flow
NAT Gateway
On Demand Instance
Persistant storage
Read replica
Virtual Private Cloud
X.509 certificate


Amazon CloudWatch collects and tracks metrics for your AWS resources. If you are new to AWS and are using the free tier you may want to add a Billing Alarm to make sure you don't run into any unexpected charges. It's easy to forget something is running and get landed with a bill.

Learn more about CloudWatch with Kyle


An S3 bucket is where objects are stored, similar to files and folders on your local machine. Each object consists of:

  • Key - the name of the object
  • Value - the data in the file itself made of bytes
  • VersionID
  • Metadata

There are four storage tiers:

  • S3 - Most expensive and reliable option
  • S3:IA - For storing non-critical data that CANNOT be easily reproduced and needs to be retrieved quickly
  • S3:IA-One Zone - For storing non-critical data that CAN be easily reproduced and needs to be retrieved quickly.
  • Glacier - Extremely cheap long-term storage
  • Deep Glacier - For long-term storage with a 12 hour retrieval time for 'cold' data

Learn more about S3 with David


The AWS CLI allows you to issue commands from the command line. It's useful for uploading files to S3 buckets and launching EC2 instances.

Learn more about the CLI:

DB Snapshot

Amazon RDS creates a storage volume snapshot of your entire instance. Creating this snapshot results in a brief I/O suspension that can last from a few seconds to a few minutes. Multi-AZ DB instances are not affected by this I/O suspension since the backup is taken on the standby.

When you create a DB snapshot, you need to identify which DB instance you are going to back up, and then give your DB snapshot a name so you can restore from it later. You can do this using the AWS Management Console, the AWS CLI, or the RDS API.

Learn how to automate this process with Jeremy

Edge location

Amazon CloudFront is the AWS CDN. It caches information closest to the user to the next user can download a copy faster. CloudFront can distribute all website content including dynamic, static, streaming and interactive content from either AWS services like S3 or your own non-AWS server.

Learn more about CloudFront with Kyle


Amazon Kinesis Data Firehose is a reliable way to stream data in near real-time. Data can be streamed to S3, Amazon's data warehousing solution, Redshift or Elasticsearch.

Kinesis allows data to be streamed in real-time from a Producer to a Processer or Storage option. This is a huge change from Batch Processing that has been the traditional way to land data from one location to another.


AWS Identify and Access Management allows you to securely control individual and group access to your resources.

Users by default have no access until you assign them a role. Roles define a set of permissions for making AWS service requests and are most often used to assign Groups of Users permissions to perform tasks or access services.

Learn more about IAM with David's practical example:

Hosted Zone

Amazon Route 53 is Amazons Domain Name System (DNS) web service. It is designed to give developers a cost-effective way to route end users to Internet applications by translating names like www.example.com into the numeric IP addresses like that computers use to connect to each other.

AWS named the service Route 53 because all DNS requests are handled through port 53.

Learn more about hosting a static website with Mario

Instance Type

EC2 is a service that provides virtual machines in the cloud where you only pay for the capacity you use and choose from ‘families’ of instance types that are good for different use cases.

General Purpose - a balance of compute, memory and networking resources
Compute Optimised -ideal for compute-bound applications that benefit from the high-performance processor
Memory-Optimised - fast performance for workloads that process large data sets in memory
Accelerated Optimised - hardware accelerators, or co-processors
Storage Optimised - high, sequential read and write access to very large data sets on local storage

Job Flow

Amazon EMR provides a scalable framework so you can run Spark and Hadoop processes over an S3 data lake. The Run Job on an EMR template launches an Amazon EMR cluster based on the parameters provided and starts running steps based on the specified schedule. Once the job completes, the EMR cluster is terminated.

There is a growing list of other services that AWS offers for data science and machine learning, learn more about them with Julien


The AWS KMS Service makes it easy to create and control encryption keys on AWS which can then be utilised to encrypt and decrypt data in a safe manner. The service leverages Hardware Security Modules (HSM) under the hood which in return guarantees security and integrity of the generated keys.

Learn more about how to get started with Mathias


To manage your objects so that they are stored cost-effectively throughout their lifecycle, configure their lifecycle. A lifecycle configuration is a set of rules that define actions that Amazon S3 applies to a group of objects. For example, you might choose to transition objects to the S3:IA storage class 30 days after you created them, or archive objects to the Glacier storage class one year after creating them.

Learn more in this practical example:


Amazon SNS allows applications to send time-critical messages to multiple subscribers through a “push” mechanism, eliminating the need to periodically check or “poll” for updates

Amazon SQS stores messages in a queue. SQS cannot deliver any messages, where an external service (lambda, EC2 etc) is needed to poll SQS and grab messages from SQS.

By using Amazon SNS and Amazon SQS together, messages can be delivered to applications that require immediate notification of an event, and also persisted in an Amazon SQS queue for other applications to process at a later time.

Learn more about how it all fits together with Frank

NAT Gateway

A virtual private cloud (VPC) is a virtual network dedicated to your AWS account. It is logically isolated from other virtual networks in the AWS Cloud. You can launch your AWS resources, such as Amazon EC2 instances, into your VPC.

You can use a NAT device to enable instances in a private subnet to connect to the internet (for example, for software updates) or other AWS services, but prevent the internet from initiating connections with the instances. A NAT device forwards traffic from the instances in the private subnet to the internet or other AWS services, and then sends the response back to the instances.

On Demand Instance

There are multiple ways to pay for Amazon EC2 instances:

  • On-Demand - pay for capacity by per hour or per second depending on which instances you run.
  • Reserved Instances - provide a reservation at 75% off the On-Demand price, giving you confidence in your ability to launch instances when you need them.
  • Spot Instances - request spare Amazon EC2 computing capacity for up to 90% off the On-Demand price.
  • Dedicated Hosts - provide EC2 instance capacity on physical servers dedicated for your use.
  • Savings Plan - provides the benefits of Reserved Instances but with more flexibility to change instance type within the same family while taking advantage of savings

Learn more about pricing with Chris

Persistant storage

Amazon EBS is a persistent storage device that can be attached to a single EC2 instance to be used as a file system for databases, application hosting, and storage.

Amazon EFS is a managed network file system that can be shared across multiple Amazon EC2 instances and is scalable depending on workload.

Learn more about provisioning EBS with Ashan


Amazon RDS makes it easy to provision a managed database instance in the cloud. At the time of writing the following database engines were available.

  • Amazon Aurora for MySQL and PostgreSQL
  • MySQL
  • PostgreSQL
  • MariaDB
  • Oracle
  • MS SQL Server

For cases when a NoSQL database is more appropriate AWS offers DynamoDB. Netflix uses DynamoDB to run it's A/B testing and personalisation experiments.

Learn more about DynamoDB with Ivan

Read replica

Read replication can be part of your disaster recovery plan. Replication means that a secondary database is online and can be queried. This is not only good for disaster recovery but can be useful if you utilise one instance for reporting and one for live queries.

If you are using AWS setting this up takes just a few clicks. You can promote a read replica if the source database instance fails or route traffic here to reduce the load on the source database.


Auto Scaling launches and terminates Amazon EC2 instances automatically according to user-defined policies, schedules, and alarms. You can use Auto Scaling to maintain a fleet of AWS EC2 instances that can adjust to any presented load. You can also use Auto Scaling to bring up multiple instances in a group at one time.

Learn more with this overview from mayank


Using tags in your metadata helps to identify who is using each resource and gain some control over costs. You can then use these in conjunction with the Monthly Billing Report

Learn more about what you should consider when trying to manage costs with Michael


Metrics are the fundamental concept in CloudWatch. A metric represents a time-ordered set of data points that are published to CloudWatch. Think of a metric as a variable to monitor, and the data points represent the values of that variable over time.

Each data point has a timestamp and a unit of measure. When you request statistics, the returned data stream is identified by namespace, metric name, dimension, and the unit.

Learn how to put this into practice with Alex by creating a Cloudwatch alarm using Lambda, CloudWatch and SNS.


A Virtual Private Cloud (VPC) is a virtual data center which is a logically isolated section of AWS that can span availability zones. VPC’s are made of Internet Gateways/Virtual Private Gateways, route tables, network access control lists, subnets, and security groups.


AWS Web Application Firewall (WAF) protects web applications from attacks, like specific user-agents, bad bots, or content scrapers, by filtering traffic based on rules that you create.

Block IP addresses that exceed request limits
This lets you control access by IP address, country, blocking SQL injections, malicious scripts and the length of requests.

Block IP addresses that submit bad requests
This solution allows you to block IP addresses using Lambda, CloudWatch and AWS WAF to block requests after a threshold has been reached.

AWS WAF can be deployed on Amazon CloudFront, protecting your resources and content at the Edge locations. And the Application Load Balancer (ALB), to protect Internet-facing as well as internal load balancers.

Learn more about making it work for you with Cloudfront with Rob

X.509 certificate

You can use x.509 certificates in AWS Certificate Manager to identify users, computers, applications, services, servers, and other devices internally.

Learn how this works with Erik


OK, I cheated here, but this is a really interesting post from Kevin and puts it all together.

Fun fact: a yobibyte is 2^80 or 1,208,925,819,614,629,174,706,176 bytes.


One of the most important introductory concepts to understand is that AWS hosts its infrastructure in data centres called Availability Zones (AZs). There are multiple AZs in a Region which means that if there is a problem in one AZ another can pick up the slack. For some services, you can host your application in multiple Regions.

Learn why you should take this into consideration when building on AWS with Frank

This post first appeared on helenanderson.co.nz

Posted on by:

helenanders26 profile

Helen Anderson


Making applications go faster at Raygun, AWS Data Hero, and tag moderator on Dev.to.


Editor guide

Good write up. :)

This year I did the SAA and DA exams and yes it was crazy.

Many AWS services have strange names that don't imply what they are doing and an even bigger amount of services is totally unknown.

Luckily, the certification exams only focus on the core stuff.

Btw. I used acloud.guru as basically my only learning resource and got stuff done pretty good. A friend of mine only did the courses there for two weeks and got both certs.

DA and SAA have about 60% overlap, so it's a good idea to do them together.


Good to know there is such a crossover, it wasn't super clear from the A Cloud Guru videos if that was still the case.

I'm tossing up whether to get the SAA and DA or move straight on to the Big Data Specialisation after the SAA. Have you found doing the certs useful in your role?


I'm a freelancer and some customers asked me if I could do AWS projects for them after they saw the certs on my homepage.

But I didn't start any AWS projects this year.

New Years resolution to build all the things? :D

Haha, probably not all the things, but a few.

Designed a shirt and wrote a book this year, so at least I did something productive.

Thought about building social2email service based on serverless tech next year.

Serverless is the future, that was the recurring theme from the Reinvent recordings :D

Yes, also I'm a front-end dev and too dumb for containers anyway 😵

That's why you have people around you can do those things. On the flipside front-end dev makes my head spin. :D


Great compilation, Helen! I really enjoy your posts, they are motivating me to write more about my learnings with AWS- I've been falling behind on the writing habit. Keep 'em coming. And many thanks for the mention!

I just passed the Solutions Architect - Associate certification this past November BTW. Feel free to DM me for anything!


I'd love to read more of your posts! The IAM and S3 writing you've done already cut the concepts down to just the essentials and were really useful.


You got this helen, SA - Assoc. is a tough one, but very doable. If you have any questions feel free to DM me. I passed mine earlier this year.


Thank you! I've found your posts really useful for putting things into context


Great article Helen. I've always been an Azure person, but have recently started to move things towards AWS and am planning on taking the certifications at some point in the near future.

Only 13 more of your articles to go now! :-)


Nice Article. Very helpful for my cert preparation.

In the Group section you mentioned "Users by default have no access until you assign them a role" does it need to be modified as "Users by default have no access until you attach them a policy"

correct me if I am wrong.



What a fantastic article. I am planning to obtain an AWS certification in the near future and I will need this.

At the rate it is feasible, can you please keep it up-to-date?


I'm certainly going to try! Next weekend's job is to go through the Exam Pro content and do an update.


Exam Pro has very quality content as far as I have checked

@andrewbrown has done an incredible job at creating beginner-friendly content. I'm looking forward to revisiting the videos and cheatsheets :D


Not a fan of AWS but definitely useful to know all the services. A lot of people use them.


Thanks for writing this.
My SAA exam is on 1st of June and this is extremely helpful!


That's so nice to hear, you're welcome.

All the best with the exam! Let me know how you go :)


Helen thank u for this informative article.
I wanna ask you how to migrate free account to paid for some limited resources problem.


TX Helen for your work :)


Thanks Helen for this content, I've started learning AWS right now and your content has been pretty helpful for me.


Great article! So, I found this infographics about the all services AWS: awsgeek.com


Nice article Helen. Got some new topics there.

I believe you can add this in the AWS CLI section. Haha.


Done! Thanks for sharing!


Love how you found a dev.to post for every topic :-)


I’m determined to pass the exam, and it’s going to ‘take a village’ to get there :D


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