AWS Core Services

EC2 (Elastic Compute Cloud) provides resizable virtual servers, called instances, that you launch on demand in the cloud. You choose an instance type defining CPU, memory, and networking, pick an AMI (machine image), and pay for the capacity you use. EC2 underpins many workloads, from web servers to batch processing, and integrates with auto scaling and load balancers for elasticity. It gives you control over the operating system, making it the flexible, general-purpose compute foundation of AWS.

S3 (Simple Storage Service) is durable, scalable object storage where you store files, called objects, inside buckets. It is designed for very high durability and can hold anything from images to backups to data-lake files, with no practical capacity limit. Objects are accessed via keys and HTTP APIs, and features include versioning, lifecycle policies, and fine-grained access control. S3 is a cornerstone of AWS, frequently used for static website hosting, backups, and as a data source for analytics.

Lambda is a serverless compute service that runs your code in response to events without you managing servers. You upload a function, and Lambda executes it when triggered by sources like an API call, an S3 upload, or a queue message, automatically scaling with demand. You pay only for the compute time consumed. Lambda suits event-driven workloads, glue code, and microservices, freeing you from provisioning and patching infrastructure, though functions have execution time and resource limits to consider.

A VPC (Virtual Private Cloud) is a logically isolated section of the AWS cloud where you define your own virtual network. You control the IP address range, create subnets, configure route tables, and attach gateways for internet or private connectivity. Security groups and network ACLs govern traffic. A VPC lets you place resources like EC2 instances in public or private subnets, mirroring an on-premises network architecture while giving fine control over isolation, routing, and security boundaries.

IAM (Identity and Access Management) controls who can do what in your AWS account. You create users, groups, and roles, and attach policies, JSON documents that grant or deny specific actions on specific resources. Roles let services or temporary sessions assume permissions without long-lived credentials. Following the principle of least privilege, you grant only the access needed. IAM is foundational to AWS security, governing access across virtually every other service in the account.