Simply, the AWS Well-Architected Framework helps you understand the pros and cons of decisions you make while building systems on AWS. It is a set of best practices for building secure, high-performance, resilient and efficient infrastructure. These best practices are a distillation of years of observation of cloud based projects. There are 5 pillars of the AWS Well-Architected Framework. Operational excellence, security, reliability, performance excellence, and cost optimization. There are also several “lenses” to highlight specific types of workloads including serverless applications, high performance computing, and internet of things.
The operational excellence pillar covers how to run systems efficiently and reliably. The key areas considered include performing operations as code, annotated documentation, making small, frequent, reversible changes, anticipating failure, and learning from operational failures. The overall philosophy is to automate, monitor, analyze, and make your operations as reliable as possible, all while continually improving.
The security pillar concentrates on the ability to protect information, systems, and assets while delivering business value through risk assessment and mitigation strategies. Topics covered include a strong identity foundation and enforcement of the principle of least privilege, enabling real-time traceability for all actions taken in your environment, applying security at all layers, not just the outer layer, automating security best practices, protecting data in transit and data at rest, eliminating human processing and access to data, and preparation for security events.
The reliability pillar encompasses the ability of a system to recover from infrastructure or service disruptions, dynamically scaling, and mitigating disruptions. Topics included are testing recovery procedures, automatically recovering from failure, scaling horizontally to increase system availability, not guessing capacity needs, and managing change in automation.
The performance efficiency pillar focuses on efficiently using resources. The primary topics include democratizing advanced technologies, going global in minutes, using serverless architectures, experimenting more, mechanical sympathy or using the technology that best aligns with the goal, and resource selection.
And lastly, the cost optimization pillar delves into avoiding unnecessary costs. Key topics include adopting a consumption model, measuring overall efficiency, stopping spending on data center operations, analyzing and accounting for expenditure, using managed services to reduce the cost of ownership.
As you can see, common themes of well-architected systems are automation, monitoring, continual process improvement, and preparation for failure.