VPC endpoints enable you to privately connect your VPC to services hosted on AWS without requiring an Internet gateway, a NAT device, VPN, or firewall proxies. Endpoints are horizontally scalable and highly available virtual devices that allow communication between instances in your VPC and AWS services. Amazon VPC offers two different types of endpoints: gateway type endpoints and interface type endpoints.

Gateway type endpoints are available only for AWS services including S3 and DynamoDB. These endpoints will add an entry to your route table you selected and route the traffic to the supported services through Amazon’s private network.

Interface type endpoints provide private connectivity to services powered by PrivateLink, being AWS services, your own services or SaaS solutions, and supports connectivity over Direct Connect. More AWS and SaaS solutions will be supported by these endpoints in the future. Please refer to VPC Pricing for the price of interface type endpoints.

You may connect your VPC to:

• The Internet (via an Internet gateway)
• Your corporate data center using a Hardware VPN connection (via the virtual private gateway)
• Both the Internet and your corporate data center (utilizing both an Internet gateway and a virtual private gateway)
• Other AWS services (via Internet gateway, NAT, virtual private gateway, or VPC endpoints)
• Other VPCs (via VPC peering connections)

No. You do not need an Elastic IP address for all your instances. By default, every instance comes with a private IP address and an internet routable public IP address. The private address is associated exclusively with the instance and is only returned to Amazon EC2 when the instance is stopped or terminated. The public address is associated exclusively with the instance until it is stopped, terminated or replaced with an Elastic IP address. These IP addresses should be adequate for many applications where you do not need a long lived internet routable end point. Compute clusters, web crawling, and backend services are all examples of applications that typically do not require Elastic IP addresses.

Amazon S3 is a simple key-based object store. When you store data, you assign a unique object key that can later be used to retrieve the data. Keys can be any string, and they can be constructed to mimic hierarchical attributes. Alternatively, you can use S3 Object Tagging to organize your data across all of your S3 buckets and/or prefixes.

Amazon RDS manages the work involved in setting up a relational database: from provisioning the infrastructure capacity you request to installing the database software. Once your database is up and running, Amazon RDS automates common administrative tasks such as performing backups and patching the software that powers your database. With optional Multi-AZ deployments, Amazon RDS also manages synchronous data replication across Availability Zones with automatic failover.

Since Amazon RDS provides native database access, you interact with the relational database software as you normally would. This means you're still responsible for managing the database settings that are specific to your application. You'll need to build the relational schema that best fits your use case and are responsible for any performance tuning to optimize your database for your application’s workflow.

• RDS for Amazon Aurora: No limit imposed by software
• RDS for MySQL: No limit imposed by software
• RDS for MariaDB: No limit imposed by software
• RDS for Oracle: 1 database per instance; no limit on number of schemas per database imposed by software
• RDS for SQL Server: 30 databases per instance
• RDS for PostgreSQL: No limit imposed by software