AWS has a global infrastructure to ensure high availability and low latency. 2 concepts to keep in mind:
Region: area where the AWS servers are located, isolated by default;
Availability Zones: there are 2 or 3 within each region and they rely on different infrastructures so they cannot get shut down contemporarily;
Edge Location: it uses CDN to cache copies locally when main server is far, can be handled with AWS Cloudfront;
How to choose a region?
Compliance requirements (if any);
Proximity to end customers;
Available features (for newest AWS services);
Pricing.
All resources are provisioned to API, there are several triggers:
Elastic Beanstalk and Cloud Formation are services used respectively for building the environment and automating it;
AWS CLI and SDK are used for scripting.
AWS VPC provisions resources privately but it has to be configured in subnets:
private subnets: resources within them cannot talk to the internet;
public subnets: resources within them can talk to the internet.
ACL are control lists are stateless and are like passport controls that check everyone who enters or exits a resource;
Security groups are stateful and are like doormen, they just check at the entrance and they remember you. Every EC2 instance has one;
The EC2 instances are ephemeral. and have cache that gets wiped out after shutting them down so data cannot be stored on them. Therefore, there are storage options:
EBS are volumes that are attached to an instance and provide storage. Great when a big file has to be edited, like a video or a photo. It is on Availability Zone level.;
S3 is a simple storage that has huge capacity, great for storing assets. It is serverless and regionally-distributed. Great when many files are fully-needed fast. According to the retrieval time, it has the “infrequent access” and “glacier” options: these are way cheaper than S3 standard so make sure to move items from standard to glacier when they are not trendy anymore;
EFS interacts with multiple EC2 instances and it’s on a regional level. More or less like EBS.
