In today's rapidly evolving digital landscape, building scalable, secure, and cost-effective applications is essential. As more organizations embrace serverless architectures, it becomes increasingly important to ensure that these applications are "well architected" to handle unpredictable scenarios, perform efficiently, and remain resilient. In this blog, we will explore key principles and best practices for creating well-architected applications, particularly focusing on AWS Lambda. These insights are derived from a talk by Shridhar Pandey, Senior Product Manager at AWS Lambda, covering the essentials of well-architected serverless applications.

You may watch the video here: https://sedai.wistia.com/medias/77fplzm700

Understanding Well Architected

What Does Well Architected Mean?

One of the first questions teams must ask is: "Are you well architected?" At first glance, the answer might seem obvious—teams consist of smart, capable people. However, it's important to pause and truly consider what being "well architected" entails.

Before diving into the specifics, consider this principle: Everything fails all the time, so plan for failure to prevent it. As Dr. Werner Vogel, CTO of Amazon, said, failure is inevitable—whether due to edge cases, unpredictable events, or system issues. Instead of ignoring potential failures, teams must embrace them and design applications that can handle these scenarios.

Characteristics of a Well Architected Application

Before we define what a well-architected application is, let's understand its key characteristics:

• Security: Ensuring that unauthorized users or malicious actors do not access your software or system.
• Resilience: The ability to recover from errors, issues, or system failures with a reasonable degree of certainty.
• High Performance: Applications must perform tasks efficiently while meeting a specific performance benchmark.
• Cost-effectiveness: The balance between performance, security, and resilience must be achieved without unnecessary costs.

When designing a serverless application for AWS Lambda, these core characteristics should guide your architecture to ensure your system can handle real-world challenges.

Building a Well Architected Application

Creating a well-architected system requires adhering to a set of principles and best practices. These principles, however, are not one-size-fits-all; they will vary depending on the organization's goals, business outcomes, and the nature of the project.

Here are some guiding points for building a well-architected application:

• Standardize Best Practices: Ensure that your team or organization follows a defined set of principles to promote consistency.
• Scalability: Build scalable tools that can be used across multiple teams or projects.
• Compliance: Audit your architecture regularly to ensure compliance with the defined principles and take necessary actions to address gaps.

Benefits of Well Architected Architecture

Now, why should teams focus on creating well-architected applications in the first place? Here's a look at the advantages:

• Problem Detection: Following structured guidelines allows you to foresee potential problems and fix them before they cause issues.
• Faster Deployment Cycles: Codified best practices help you identify and mitigate risks early, which speeds up deployment cycles.
• Benchmarking: A well-architected framework allows you to measure and compare your architecture against business outcomes. For example, if you need low latency for your application or are building for scalability, your architecture should meet those specific needs.

Turning Good Intentions into Mechanisms

Good intentions are important, but at AWS, there's a saying: "Good intentions never work. Mechanisms do." 

In the context of creating well-architected applications, this means that it's not enough to have a theoretical understanding of best practices. You need a set of mechanisms to enforce and measure compliance with those principles.

The Three-Step Model for Mechanisms:

1. Define and Learn Best Practices: Ensure everyone is aligned on the principles and strategies that guide architecture.
2. Measure Compliance: Compare your architecture against these standards regularly.
3. Improve and Iterate: Based on the measurements, address issues and evolve your architecture over time.

This continuous improvement cycle feeds back into the learning process, creating a robust architecture that adapts to changing needs and challenges.

Introduction to AWS Well Architected Framework

The AWS Well Architected Framework, or simply AWS Well Architected, emerged in 2012. AWS began asking a critical question to its users: Are you well architected? Initially, the framework focused on four key pillars:

• Cost-effectiveness
• Optimization
• Resiliency
• Security

AWS continuously refined these pillars and questions based on reviews conducted by its solution architects. Over time, a fifth pillar, Operational Excellence, was added, and by 2020, AWS introduced the Serverless Application Lens as a way to guide serverless development. In 2021, AWS further innovated with Custom Lenses, enabling organizations to create their own frameworks.

Overview of the AWS Well Architected Framework

At its core, the AWS Well Architected Framework provides a set of design principles and questions to help organizations achieve their desired business outcomes. The framework spans six pillars, and each pillar includes a series of best practices designed to address specific architectural challenges.

Here’s a look at the six pillars of the AWS Well Architected Framework:

1. Operational Excellence
2. Security
3. Reliability
4. Performance Efficiency
5. Cost Optimization
6. Sustainability

These pillars serve as guidelines for AWS customers to implement solutions based on AWS best practices developed over the years.

Serverless Application Lens

The Serverless Application Lens within the AWS Well Architected Framework applies the general principles to serverless architectures. It incorporates AWS serverless services, including Lambda, Fargate, API Gateway, DynamoDB, S3, and others. Each layer of serverless infrastructure—whether compute, storage, or messaging—is considered within this lens. This specific lens ensures that serverless applications adhere to the six pillars mentioned earlier.

AWS Serverless Solutions Overview

AWS offers a wide range of serverless solutions across several layers of infrastructure. While this list is not exhaustive, it gives a glimpse into AWS’s offerings:

• Compute: Lambda, Fargate
• Access: API Gateway, Step Functions
• Storage: DynamoDB, S3
• Messaging and Streaming: SQS, EventBridge, Kinesis

This framework ensures that AWS’s serverless solutions meet various architectural demands, from scalability to performance efficiency.

Core Principles for Serverless Architecture

When designing serverless applications, it’s crucial to follow specific design principles. These principles ensure that the applications remain efficient, scalable, and cost-effective.

• Speedy, Simple, and Singular Functions: Serverless functions, like Lambda, should be short, single-purpose units that complete their task within the request's lifecycle.some text
  • Concurrent Requests Focus: Instead of total requests, focus on how many requests are processed concurrently.
  • No Hardware Affinity: AWS Lambda optimizes infrastructure automatically, so developers should not assume that the same hardware or resources will be used for subsequent requests.
  • Orchestration with State Machines: Use state machines, such as AWS Step Functions, instead of chaining several Lambda functions to handle complex workflows.
  • Event-Driven Architecture: Serverless systems should capitalize on AWS’s event-driven capabilities to make the architecture leaner and more efficient.
  • Idempotency: Applications must handle failures and duplicates by ensuring they can recover without affecting the overall system.

The Six Pillars of AWS Well Architected Framework for Serverless

Let’s explore the six pillars of the Well Architected Framework, particularly in relation to serverless applications.

1. Operational Excellence: This focuses on supporting development and operations to run workloads effectively, gain insights, and improve processes. For serverless, this means deploying and operating applications quickly and efficiently.
2. Security: Protecting information, systems, and assets while delivering business value is a core priority.
3. Reliability: The ability of a system to recover from failure and meet customer demands is crucial in serverless systems where resources may change dynamically.
4. Performance Efficiency: Leveraging IT and computing resources efficiently is key. Serverless solutions like Lambda ensure performance by automatically scaling.
5. Cost Optimization: Serverless systems help manage costs effectively by charging based on actual usage.
6. Sustainability: The latest pillar, sustainability, focuses on minimizing the environmental impact of IT systems by utilizing energy-efficient cloud infrastructure.

AWS Serverless Deployment Flow

The deployment of serverless applications follows a distinct flow, encompassing designing, architecting, deploying, and operating serverless solutions. By adhering to well-architected principles, you can ensure more efficient, cost-effective, and high-performing applications .

Operational Excellence Pillar

Operational Excellence focuses on the ability to manage and run a system efficiently to deliver business value. This includes ensuring the system operates as intended, meets performance and reliability standards, and continuously improves through process and procedural enhancements.

Key Best Practices for Operational Excellence

Operational excellence is built on several best practices, each of which contributes to the overall functionality and efficiency of a system. These best practices can be broken down into four main areas:

• Organizational Best Practices: Ensure teams have a shared understanding of the workload and well-defined roles within the process. Having clarity on priorities and responsibilities is critical for maximizing outcomes.
• Prepare: Understand the behavior of systems by aligning input goals with output metrics. It’s essential to know the expected performance of each team, component, and application.
• Operate: Define operational principles, including setting parameters for system behavior, understanding steady states, and identifying signs of degradation or failure.
• Evolve: Continuously improve the system by feeding insights gained through monitoring back into the process for future refinement.

Questions to Evaluate Operational Excellence

When going through a Well Architected Review, several key questions help evaluate whether the system is well-architected. For example:

• How does your organization utilize workload observability?
• Are you using the right metrics to understand system health and performance?
• How do you preemptively handle potential operational issues, such as increasing latency or resource failures?

These questions guide teams in ensuring that best practices are effectively implemented and optimized for operational excellence.

Metrics for Operational Excellence

To properly evaluate and improve system operations, organizations should track several types of metrics:

• Business Metrics: These could include the volume of orders processed per time frame and the success rate of transactions.
• Customer Experience Metrics: Measure how long customers take to complete key tasks, such as landing on a homepage and submitting an order.
• System Metrics: This includes tracking the health of underlying infrastructure, such as memory utilization and execution duration in a serverless environment like AWS Lambda.
• Operational Metrics: These internal metrics evaluate the efficiency of business logic, such as delays between systems or communication processes.

Best Practices in Action

For example, structured logging helps teams easily search and filter logs while debugging issues. Adding metadata, such as order or customer IDs, to logs helps teams analyze specific business scenarios. In distributed applications, distributed tracing offers a bird’s-eye view of all system components. Centralizing logs and ensuring they are searchable is crucial for debugging and maintaining operations.

Performance Efficiency Pillar

A well-architected application should be high performing, meeting the business’s performance KPIs and SLAs. In distributed systems or cloud applications, teams need to make efficient use of compute resources, regardless of the platform used.

Best Practices for Performance Efficiency

The first step in performance efficiency is selecting the right compute platform. This decision depends on factors like whether the application is bursty or has a steady-state flow. Best practices for optimizing performance include:

• Right-Sizing Compute Resources: Assign resources that meet your performance needs without overspending.
• Periodic Review: Regularly review your system’s performance to ensure the compute resources and scaling decisions are still appropriate.
• Monitoring for Decision Support: Continuously monitor performance to evaluate whether your initial decisions about resource allocation are still valid. This can involve adjusting for latency, scaling, and resource optimization based on monitoring data.

Best Practices in Action

For instance, timeout optimization ensures that applications are not assigned more time than needed, avoiding unnecessary resource usage. Minimizing the size of deployment packages can also reduce startup time. Finally, reusing execution environments, especially in AWS Lambda, can lead to better performance by reducing the overhead of repeated initialization.

Cost Optimization Pillar

Cost Optimization is about continuously refining and improving system efficiency to maximize return on investment over time. Best practices in this area focus on using the most cost-effective resources, such as selecting the right balance between memory and compute power.

Best Practices for Cost Optimization

Key strategies include:

• Cost-Effective Resource Selection: Choose the most appropriate resource type based on your workload’s specific needs, whether it’s interactive or spiky.
• Build Cost Awareness into Applications: Ensure that applications are aware of their resource usage to avoid overspending, particularly in environments like AWS Lambda.
• Optimize Over Time: Regularly evaluate and optimize your system’s performance and costs to avoid stagnation and unnecessary expenses.

Questions to Ask for Cost Optimization

• How do you evaluate new services and features from a cost perspective?
• Are the benefits of new features outweighed by the engineering effort required to implement them?

By continually asking these questions, organizations can ensure that they are not over-investing in resources they don’t need.

Cost Optimization in Action

Using tools like Lambda Power Tuning helps optimize memory allocation for AWS Lambda functions. Similarly, utilizing Graviton processors can offer cost-performance benefits over traditional architectures. Another example is using auto-scaling instead of provisioning excessive resources when application traffic follows predictable patterns.

Components of the AWS Well Architected Framework

The AWS Well Architected Framework is composed of various components designed to guide organizations in building secure, efficient, and scalable applications. These components include:

• Pillars and Lenses: Framework pillars such as operational excellence, security, and cost optimization serve as the foundation. Lenses, such as the Serverless Application Lens, help apply these principles to specific use cases.

Resources Available for AWS Well Architected

There are several resources available to help organizations implement the AWS Well Architected Framework:

• Training and White Papers: AWS provides a wealth of training material and white papers to help you get started with the framework.
• Evaluation Tools: There are tools available to assess workloads, evaluate metadata, and even engage with AWS experts to review your architecture.
• AWS Well Architected Tool: This is one of the most helpful resources. The Well Architected Tool is free to use, and it allows teams to evaluate their workloads against best practices.

The Well Architected Tool is an excellent starting point for any organization looking to assess and improve their AWS architecture. It offers a step-by-step process to ensure your application aligns with AWS best practices, whether or not you’re using serverless solutions.

Understanding "Are You Well Architected?"

When AWS asks, “Are you well architected?” it means more than just whether your application is functioning. It asks whether you have gone through a series of evaluations and applied a set of quantitative rules and processes to ensure your architecture is optimized. This evaluation helps provide a clear yes or no answer to the question, helping teams confirm whether they meet the AWS Well Architected standards.

Conclusion

The AWS Well Architected Framework offers a clear path for building secure, efficient, and scalable applications, especially for serverless environments like AWS Lambda. By following its six pillars—operational excellence, security, reliability, performance efficiency, cost optimization, and sustainability—organizations can ensure their systems are optimized for success.

Using the AWS Well Architected Tool and regularly evaluating your architecture ensures that your applications remain adaptable, cost-effective, and high-performing. Ultimately, being well architected is about continuous improvement, ensuring your system consistently delivers value and meets business needs.