AWS Compute Blog

Building well-architected serverless applications: Introduction

The following posts are a multi-part series addressing each of the questions within the Serverless Lens of the Well-Architected Tool.

Series Episodes: Building well-architected serverless applications

  1. Introduction
  2. Operational Excellence: Understanding serverless application health
    1. Out of the box metrics and alerts; structured and centralized logging
    2. Custom metrics and distributed tracing
  3. Operational Excellence – Approaching application lifecycle management
    1. Using infrastructure as code with version control
    2. Deploying to multiple stages using temporary environments, and rollout deployments
    3. Configuration management, CI/CD, and managing function runtime deprecation
  4. Security – Controlling access to serverless APIs
    1. Authentication and authorization for public and private API endpoints
    2. Amazon Cognito user and identity pools, JSON web tokens, API keys and usage plans
    3. Separating authenticated users into logical groups
  5. Security – Managing serverless security boundaries (upcoming)
  6. Security – Implementing application security (upcoming)
  7. Reliability – Regulating inbound request rates (upcoming)
  8. Reliability – Building resiliency into serverless applications (upcoming)
  9. Performance Efficiency – Optimizing your Serverless Application Performance (upcoming)
  10. Cost Optimization – Optimizing your Serverless Application Costs (upcoming)

Well-architected

Customers building production applications in the cloud are looking to build and operate their applications following best practices. Best practices are useful throughout the software development lifecycle and help to answer the question “am I well-architected?”

Serverless technologies provide a solid foundation for building well-architected applications with a goal to reduce and minimize the impact of issues that can happen. What does it mean to be “well architected”?

In 2015, AWS released the AWS Well-Architected Framework.  It’s a structured way to compare applications against AWS architectural best practices with advice on how to improve. This formalized framework publicly documents the approach our solutions architects use when conducting architectural reviews. The Well-Architected Framework can be used by customers and partners to evaluate applications. It’s currently based on five pillars:

  • Operational Excellence
  • Security
  • Reliability
  • Performance Efficiency
  • Cost Optimization

In 2017, AWS extended the framework’s general advice to be more application domain specific with the concept of a “lens”. A lens adds additional questions for specific technology areas, which focus on what is different from the generic advice. Today, there are three technology domain lenses:

In 2018, AWS added the AWS Well-Architected Tool within the AWS Management Console. The tool allows you to define a Workload and answer a number of questions based on each of the five pillars. Each question has context to explain what the question means and why it is important, and then provides a number of best practices.

Well-Architected Tool question

Well-Architected Tool question

The tool is used to assess risks, and find opportunities for improvement for workloads. It can also provide a broader view across multiple applications for a central team. Each question has a number of best practices to follow, categorized as high or medium risk. This can help you decide where to focus.

Serverless Lens

In February, we added functionality to apply lenses to the Well-Architected Tool. The first one is the Serverless Lens. This includes nine questions, each with additional best practice recommendations to follow.

Serverless Lens in console

Serverless Lens in console

Applying best practices to production applications may need some more time and effort. The Well-Architected Tool and Serverless Lens are available to help and are not intended to only be a one-time check.

We suggest at a minimum reading the whitepapers and being familiar with the questions before the design phase. It’s a good idea to check throughout the application lifecycle; halfway (or sooner), close to launch, and post-launch for each iteration. Although it is never too late to add best practices to your applications, starting early helps reduce the remediation process as well as making it part of the full application lifecycle journey.

Example application

For this series, I am looking at an example application, AWS Serverless Airline Booking. This is a complete web application for a fictional airline booking service built using serverless technologies that provide Flight Search, Payment, Booking, and Loyalty Point features.

I show how to use the Well-Architected Tool with the Serverless Lens to help apply serverless best practices to the application.

Airline mobile example screenshots

Airline mobile example screenshots

This web application is the theme of Season 2 of Build on Serverless, which is a video series on Twitch.tv, and presented at AWS re:Invent 2019.

You can view this application directly on GitHub or deploy into an AWS account using the Getting Started instructions. This is not required to follow this Building Well-Architected Serverless Applications series but allows you to explore the code.

The application architecture consists of a frontend web application, which interacts with a number of backend microservices to provide the airline booking functionality.

Airline architecture diagram

Airline architecture diagram

There are four backend services that make up the application:

Service Description
Catalog Provides flight search
Booking Provides new and list bookings. Business workflow implemented in Python.
Payment Provides payment authorization, collection, and refund workflows using Stripe. Business workflow implemented in Python
Loyalty Provides loyalty points for customers including tiers. Implemented in TypeScript.

Once the application is deployed, I can create a booking by searching for flights.

Search flight

Search flight

Select flight

Select flight

Once I select an available flight, I enter payment details using a test Stripe credit card.

Flight Payment

Flight Payment

The application authorizes the payment, confirms, and stores the booking and then updates the loyalty points.

Flight confirmed

Flight confirmed

Next steps

Building serverless applications using best practices can give you more confidence in the architecture and operations of your workloads.

Using the Well-Architected Tool and Serverless Lens can give you more visibility into your applications. They can help pinpoint and rank areas to improve. Well-Architected works best when integrated into your application lifecycle processes.

Continue learning in the next post, which dives into the first Well-Architected Serverless Lens question: Operational Excellence – Understanding Serverless Application Health – part1.