AWS Global Infrastructure

What is the active-active topology?

A computing cluster operates with a minimum of two nodes, and each one brings the same kind of service simultaneously; this is called active-active. The purpose of this topology is to load balance and avoid single points of failure (SPOF).

What is AES-256?

A standard symmetric encryption algorithm on the server side to improve the at-rest security of our data and ensure information confidentiality.

What is the overall benefit of AWS Regions?

AWS Regions are a means to deliver applications and services with a global footprint, allowing the elasticity of resources and information synchronization with a high level of control and isolation.

What does ACL stand for?

Access Control List

How many geographic regions and how many total availability zones does the global infrastructure of AWS have?

At the time of the writing of this book, AWS has 15 geographic regions and a total of 54 Availability Zones and three private regions; one in the US (GovCloud) and two more in China (Beijing and Ningxia). So, AWS is positioned as the cloud provider with the most significant infrastructure in the world when it comes to data centers.

What is the first decision to make when designing in AWS?

Choosing a geographic region

Some countries have laws that public service providers and data storage exist contained within the geographic limits of their nation. How could a country that does not have an AWS in their territory still use AWS?

Could use a nearby AWS region and can use additional security mechanisms such as encryption, obfuscation, and the use of secure communication channels that complement the required security objectives.

What is the purpose of the Direct Connect Gateway?

Direct Connect Gateway enables global access to private VPC resources and AWS services at a low cost; this was formerly known as inter-region connectivity, which allowed users to operate in multiple AWS Regions across the US including GovCloud, with limited access elsewhere. This new model allows users to gain interregional access to data and services, making efficient infrastructure operations with better throughput, improving the whole connectivity experience, and reducing costs significantly, compared to multiple ISP links.

What is an ETag?

ETag is an HTTP mechanism to perform cache validations

What consistency model does S3 utilize on modified objects during PUT overwrites and DELETES on existing objects?

Each modified object has an eventual consistency model for PUT overwrites and DELETES on existing objects, leading to probable stale reads if a GET or LIST operation is immediately performed. This model is less strict and yields strong consistency in favor of availability, performance, and network partition tolerance (two AZs failing simultaneously)

What consistency model does S3 utilize when creating new objects?

Each new object works on a strong consistency model called read-after-write for which every object is written in at least three different AZs before the SUCCESS code is returned, avoiding stale reads on other clients.

Why is Simple Storage Service (S3) a great option to host a static website?

Hosts every file with a 99.999999999% durability [DONE]; High availability with an SLA of 99.99%; Low cost for usage calculated for every 1,000 requests, plus storage, and data transfer fees

What is the single-region pattern?

It consists of using a single region maintaining communications and resources very closely, distributed to the AZ level.

What is the multi-region pattern?

It is to deploy services and applications globally using multiple regions with a higher reach even in different AWS accounts.

Where was the first AWS region built?

North Virginia

Can you replicate a replica is Amazon S3? If not, how could you get around doing this operation?

Objects with the REPLICA status cannot be replicated again into another bucket; this operation can only be done by using S3 APIs with the CopyObject action, which involves a GET after a PUT operation.

Which AWS region with modern hardware has become the favorite region for public releases?

Oregon

What does PoP stand for?

Point of Presence

Solve the problem: We need replication of PNG images to a second region in the same AWS account to improve data durability, and in the case of a disaster, recover 100% of data to the primary region.

Possible Solution: Two S3 buckets need to be configured; one in each region to be completely isolated and avoid sharing the same failure line. For this exercise, versioning must be enabled and cross-region replication (CRR) must be configured.

What does QoS stand for?

Quality of Service

If replication has been enabled for an object, besides the object itself, what properties will also be replicated?

Tags, ACL, Metadata, etc...all of them

As it pertains to the CDN, what are edge locations?

They are collocated resources on the edge of AWS Regions. CloudFront uses this type of infrastructure for content delivery, to access services and data efficiently in the main cities of the world. They expand the functionality of the AZs, arranging an edge location cache providing low latency for applications, and it is a Content Delivery Network (CDN).

What type of redundancy do AWS data centers implement?

They are designed to provide N+1 redundancy and have automatic recovery procedures in the cases of disaster; this provides end users have a continuity of operations in the case of a natural disaster or any other kind of service failure.

How could you utilize the cost discrepancy between different AWS regions?

This fact can play to our favor because we can execute more cost-efficient workloads in other regions rather than production, for example, development environments archiving and cold backups.

What is the active-passive topology?

This kind of cluster maintains an active primary service and a passive secondary waiting to replace the primary in the case of a failure; these clusters are commonly used in disaster recovery strategies and consist of a means to balance requests between primary and secondary services as necessary to maintain business operations, even in the case of maintenance.

What is Amazon CloudFront?

This service is responsible for maintaining multiple copies of your data in different locations for a fast search, depending on where the request is being made. Amazon CloudFront can be thought as a cache load balancer. It is also possible to use it for streaming data and an upload optimization for services like Amazon S3 with transfer acceleration enabled.

What does TCO stand for?

Total Cost of Ownership

What is AWS Direct Connect?

a service that makes it possible to access data centers throughout a dedicated connection from a Point of Presence (PoP) to AWS directly; this service can be acquired via a third-party provider by using dedicated fiber private links.

Every object in Amazon S3 is opaque. What does that mean?

every object in S3 is opaque, being that each extension and file type is meaningless. S3 is a service optimized to store vast amounts of data with high availability and amazing durability, so it does not have hierarchical capabilities like a regular file system. Imagine S3 as a considerable HashMap data structure as a service.

What is the CAP theorem?

the CAP theorem, which tells us that any distributed system in the presence of a network partition must, by nature, choose between consistency and availability.