An instance in AWS is a virtual server that can be rented on an hourly basis to deploy applications on it. It is a server resource provided by third-party cloud services. Amazon Elastic Compute Cloud (EC2) is a service that enables business subscribers to run application programs in the computing environment. When launching an instance, the instance type that is specified determines the hardware of the host computer used for the instance. Each instance type offers different compute, memory, storage, and network capabilities. The instance types are grouped into families based on target application profiles, and each family includes various sizes to address specific workload requirements. The following are some of the instance families:

• General Purpose Instances: These instances balance computing, memory, and networking resources and are suitable for various purposes such as application servers, gaming servers, and small and medium databases.

• Compute Optimized Instances: These instances are ideal for high-performance and compute-intensive needs, such as application servers, gaming servers, and web applications.

• Memory Optimized Instances: These instances can deliver large dataset workloads fast and are suitable for memory-intensive workloads such as high-performance databases and distributed memory caches.

• Storage Optimized Instances: These instances are designed for workloads that require high, sequential read and write access to large data sets, such as data warehousing and log processing.

Instances are created from Amazon Machine Images (AMI), which are pre-configured templates that wrap everything needed for the server, including the operating system and other software. Users can select an AMI provided by AWS, the user community, or through the AWS Marketplace, or create their own AMIs and share them. EC2 instances are highly scalable, meaning they can be scaled up or down based on requirements dynamically.