3.3 Identify the core AWS services

Here’s a list of the services you should definitely know. But, don’t be surprised if you see questions about others as well: The level of detail in each question depends on the service. More widely used services may require a bit more knowledge, and others will only require that you know what the service does. For example, EC2 is one of the most important AWS services, so you could be asked questions about different instance types for different scenarios. On the other hand, you may only be asked to choose the best description of a service like CloudFront.
 * EC2
 * VPC
 * S3
 * RDS
 * Lambda
 * Route 53
 * SNS
 * SQS
 * ELB

In addition to the traditional services, the exam covers other AWS technology, including the command line interface (CLI) and software development kit (SDK). You may also see questions that overlap with other exam domains. For example, services like AWS Trusted Advisor and AWS Cost Calculator may fall into the technology domain as well as billing and pricing.

EC2
Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides secure, resizable compute capacity in the cloud. It is designed to make web-scale cloud computing easier for developers.

General Purpose
T2 - T2 instances are Burstable Performance Instances that provide a baseline level of CPU performance with the ability to burst above the baseline.

M4 - M4 instances are the latest generation of General Purpose Instances. This family provides a balance of compute, memory, and network resources, and it is a good choice for many applications.

Compute Optimised
C4 - C4 instances are the latest generation of Compute-optimized instances, featuring the highest performing processors and the lowest price/compute performance in EC2.

Memory Optimised
X1 - X1 Instances are optimized for large-scale, enterprise-class, in-memory applications and high-performance databases, and have the lowest price per GiB of RAM among Amazon EC2 instance types.

R4 - R4 instances are optimized for memory-intensive applications and offer better price per GiB of RAM than R3. The RAM sizes are a step below the X1s.

Accelerated Computing
P2 - P2 instances are intended for general-purpose GPU compute applications.

G3 - G3 instances are optimized for graphics-intensive applications. The GPU specs are a step below the P2s.

F1 - F1 instances offer customizable hardware acceleration with field programmable gate arrays (FPGAs).

Storage Optimised
I3 - High I/O instances. This family includes the High Storage Instances that provide Non-Volatile Memory Express (NVMe) SSD backed instance storage optimized for low latency, very high random I/O performance, high sequential read throughput and provide high IOPS at a low cost.

D2 - Dense-storage instances. D2 instances feature up to 48 TB of HDD-based local storage, deliver high disk throughput, and offer the lowest price per disk throughput performance on Amazon EC2.

Pricing
Amazon EC2 is free to try. There are four ways to pay for Amazon EC2 instances: On-Demand, Reserved Instances, and Spot Instances & Per-Second Billing. You can also pay for Dedicated Hosts which provide you with EC2 instance capacity on physical servers dedicated for your use.

On-Demand
With On-Demand instances, you pay for computing capacity by per hour or per second depending on which instances you run. No longer-term commitments or upfront payments are needed.

Spot Instances
Amazon EC2 Spot instances allow you to bid on spare Amazon EC2 computing capacity for up to 90% off the On-Demand price. Spot instances are recommended for applications that have flexible start and end times, applications that are only feasible at very low compute prices or users with urgent computing needs for large amounts of additional capacity.

Reserved Instances
Reserved Instances provide you with a significant discount (up to 75%) compared to On-Demand instance pricing. For applications that have steady state or predictable usage, require reserved capacity or can commit to using EC2 for a 1 or 3 year period, Reserved Instances can provide significant savings compared to using On-Demand instances.

Per-Second Billing
With per-second billing, you pay for only what you use. It takes cost of unused minutes and seconds in an hour off of the bill, so you can focus on improving your applications instead of maximising usage to the hour.

Security Groups
A  security group  acts as a virtual firewall that controls the traffic for one or more instances. When you launch an instance, you associate one or more security groups with the instance. You add rules to each security group that allow traffic to or from its associated instances. You can modify the rules for a security group at any time; the new rules are automatically applied to all instances that are associated with the security group. When we decide whether to allow traffic to reach an instance, we evaluate all the rules from all the security groups that are associated with the instance.

S3
Amazon S3 is object storage built to store and retrieve any amount of data from anywhere – web sites and mobile apps, corporate applications, and data from IoT sensors or devices. It is designed to deliver 99.999999999% durability, provides comprehensive security and compliance capabilities that meet even the most stringent regulatory requirements and gives customers flexibility in the way they manage data for cost optimization, access control, and compliance. Also, S3 is the only cloud storage solution with query-in-place functionality, allowing you to run powerful analytics directly on your data at rest in S3.

Storage Classes
Amazon S3 offers a range of storage classes designed for different use cases. Lifecycle transitions can be used to move data between classes, given certain events.

Amazon S3 Standard
Designed for general-purpose storage of frequently accessed data. Delivers low latency and high throughput, perfect for a wide variety of use cases. There is no retrieval fee, minimum object size or minimum storage duration.

Amazon S3 Standard - Infrequent Access
Designed for long-lived, but less frequently accessed data. For data that is accessed less frequently, but requires rapid access when needed. Standard - IA offers the high durability, throughput, and low latency of Amazon S3 Standard, with a low per GB storage price and per GB retrieval fee.

Amazon Glacier
Designed for long-term archive. Secure, durable, and extremely low-cost storage service for data archiving. You can reliably store any amount of data at costs that are competitive with or cheaper than on-premises solutions. Amazon Glacier provides three options for access to archives, from a few minutes to several hours.

RDS
Amazon Relational Database Service (Amazon RDS) makes it easy to set up, operate, and scale a relational database in the cloud. It provides cost-efficiency and resizable capacity while automating time-consuming administration tasks such as hardware provisioning, database setup, patching and backups.

Amazon RDS is available on several database instance types - optimized for memory, performance or I/O. RDS provides you with six familiar database engines to choose from. Amazon RDS supports encryption at rest and in transit, using keys managed through KMS. Backups are automated, user-initiated snapshots are available and database software is updated automatically.

Instance Types
·         General Purpose

·         Memory Optimized

Database Engines
·         Amazon Aurora

·         PostgreSQL

·         MySQL

·         MariaDB

·         Oracle

·         Microsoft SQL Server

AWS Database Migration Service
AWS Database Migration Service can help you migrate databases to AWS easily and securely. The source database remains fully operational during the migration, minimizing downtime to applications that rely on the database. The AWS Database Migration Service can migrate your data to and from most widely used commercial and open-source databases. The service supports homogenous migrations such as Oracle to Oracle, as well as heterogeneous migrations between different database platforms, such as Oracle to Amazon Aurora or Microsoft SQL Server to MySQL.

It also allows you to stream data to Amazon Redshift, Amazon DynamoDB, and Amazon S3 from any of the supported sources including Amazon Aurora, PostgreSQL, MySQL, MariaDB, Oracle, SAP ASE, SQL Server and MongoDB, enabling consolidation and easy analysis of data in the petabyte-scale data warehouse. AWS Database Migration Service can also be used for continuous data replication with high-availability.

AWS Schema Conversion Tool
The AWS Schema Conversion Tool makes heterogeneous database migrations predictable by automatically converting the source database schema and a majority of the database code objects, including views, stored procedures, and functions, to a format compatible with the target database. Any objects that cannot be automatically converted are clearly marked so that they can be manually converted to complete the migration. SCT can also scan your application source code for embedded SQL statements and convert them as part of a database schema conversion project.

Your source database can be on-premises, or in Amazon RDS or EC2 and the target database can be in either Amazon RDS or EC2. The AWS Schema Conversion Tool supports conversions from multiple RBMS providers to an equivalent database in RDS, or from multiple data warehouse providers to Amazon Redshift.

Lambda
AWS Lambda lets you run code without provisioning or managing servers. You pay only for the compute time you consume - there is no charge when your code is not running. With Lambda, you can run code for virtually any type of application or backend service - all with zero administration.

AWS Lambda automatically scales your application by running code in response to each trigger. Your code runs in parallel and processes each trigger individually, scaling precisely with the size of the workload. With AWS Lambda, you are charged for every 100ms your code executes and the number of times your code is triggered. You don't pay anything when your code isn't running.

Route 53
Amazon Route 53 is a highly available and scalable cloud Domain Name System (DNS) web service. You can use Amazon Route 53 to configure DNS health checks to route traffic to healthy endpoints or to independently monitor the health of your application and its endpoints.

Amazon Route 53 Traffic Flow makes it easy for you to manage traffic globally through a variety of routing types, including Latency Based Routing, Geo DNS, Geoproximity, and Weighted Round Robin—all of which can be combined with DNS Failover in order to enable a variety of low-latency, fault-tolerant architectures. Using Amazon Route 53 Traffic Flow’s simple visual editor, you can easily manage how your end-users are routed to your application’s endpoints—whether in a single AWS region or distributed around the globe.

Amazon Route 53 also offers Domain Name Registration – you can purchase and manage domain names such as example.com and Amazon Route 53 will automatically configure DNS settings for your domains.

Amazon Route 53 is integrated with Elastic Load Balancing (ELB).

SNS
Amazon Simple Notification Service (SNS) is a Pub/Sub messaging and mobile notifications for microservices, distributed systems, and serverless applications. Amazon SNS Mobile Notifications makes it simple and cost effective to send push notifications to iOS, Android, Fire OS, Windows and Baidu-based devices. It supports HTTP/HTTPS, Email/Email-JSON, SMS or Amazon Simple Queue Service (SQS) queues, or AWS Lambda functions.

Amazon DevPay
Amazon DevPay is a simple-to-use online billing and account management service that makes it easy for businesses to sell applications that are built in, or run on top of, Amazon Web Services.

Amazon QuickSight
Amazon QuickSight is a fast business analytics service you can use to build visualizations, perform ad hoc analysis, and quickly get business insights from your data. You can access data from multiple sources – upload files or connect to AWS data sources or external databases.

SQS

 * 1) Fully managed message queuing service
 * 2) Lets you decouple and scale microservices, distributed systems, and serverless applications
 * 3) Eliminates the complexity and overhead associated with managing and operating message oriented middleware
 * 4) Send, store, and receive messages between software components at any volume, without losing messages or requiring other services to be available.
 * 5) Two types of message queues
 * 6) * Standard queues offer maximum throughput, best-effort ordering, and at-least-once delivery.
 * 7) * SQS FIFO queues guarantee that messages are processed exactly once, in the exact order that they are sent.

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