Mastering AWS Serverless Design Principles for Architects
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Chapter 1: Introduction to AWS Serverless Design Principles
If you have experience with AWS, you are likely aware of their distinctive operational methods. Meetings often commence with silent reading of documents, projects are approached from the end goal backward, and their leadership principles are strictly adhered to. This unique approach is a significant factor in Amazon's global influence and success.
A key aspect of their methodology is the design principles they provide to assist organizations in developing superior software solutions. Those who have participated in an AWS Well-Architected review are familiar with these principles in depth (and in a beneficial manner).
For those focused on creating serverless applications, AWS presents a tailored set of design principles. These principles adapt the core elements of the Well-Architected framework to the specific context of serverless applications.
In this discussion, we will explore all seven principles and their implications for your design approach as a solutions architect.
Section 1.1: Principle 1 - Speedy, Simple, Singular
“Functions should be brief, single-purpose, and their runtime environment should correspond to their request lifecycle. Efficient transactions favor faster executions.”
Interpretation:
Functions, particularly Lambdas, must be focused. They should initiate, complete their task, and terminate swiftly.
To optimize execution time, leverage asynchronous workflows whenever possible. For instance, place a task in an SQS queue for further processing and cease the originating Lambda's execution. Avoid invoking another Lambda from within a Lambda when feasible.
Adhere to the single-responsibility principle; if a task requires multiple actions, create separate functions for each.
Section 1.2: Principle 2 - Focus on Concurrent Requests
“Serverless applications utilize the concurrency model, and design tradeoffs are assessed with concurrency in mind.”
Interpretation:
Avoid the tendency to maximize efficiency by minimizing request count. Instead, recognize the importance of concurrency.
This principle encourages architects to capitalize on a serverless application’s capacity for horizontal scaling during peak usage. When functions are designed as suggested in Principle 1, they will respond quickly, often within milliseconds.
Even if your application is managing a high volume of requests, each user will experience the system as responsive and efficient. Thus, design your systems to leverage AWS’s automatic scaling capabilities.
Decompose lengthy tasks into smaller units when possible; this will enhance performance and reduce costs.
Section 1.3: Principle 3 - Embrace Statelessness
“Function runtime environments are transient, so local resources like temporary storage cannot be relied upon. Persistent storage is recommended for durability.”
Interpretation:
Assume that every function is stateless. Always query the database for entity state, rather than depending on globally scoped variables.
While it’s advantageous to instantiate SDK clients globally for performance enhancement, maintain a fresh execution context and load necessary resources each time.
Section 1.4: Principle 4 - Disregard Hardware Dependencies
“The underlying infrastructure can change; therefore, leverage hardware-agnostic code and dependencies.”
Interpretation:
Serverless architecture is designed to abstract away hardware considerations. Avoid getting bogged down with server-side hardware details.
Instead, utilize environment variables for configuration and optimize your functions post-implementation.
Section 1.5: Principle 5 - Utilize State Machines for Orchestration
“Chaining Lambda executions within code leads to tightly coupled applications. Employ a state machine for orchestrating transactions and workflows.”
Interpretation:
By adhering to the previous principles, you will likely develop a modular system. A single command may trigger multiple Lambdas, which is beneficial for scalability and performance.
Avoid invoking Lambdas directly from one another, as this method is slower and more costly. Instead, use Step Functions to manage workflows, providing clear visualizations and traceability.
Section 1.6: Principle 6 - Leverage Events for Transaction Triggers
“Events, such as new S3 object uploads or database updates, trigger transaction execution based on business requirements.”
Interpretation:
Embrace asynchronous operations; there’s no need for users to wait for every system action.
Utilize event-driven architecture where actions are initiated by specific events, ensuring that the system operates efficiently without unnecessary delays.
Section 1.7: Principle 7 - Prepare for Failures and Duplicates
“Operations triggered by requests/events should be idempotent, as failures can occur and requests may be duplicated.”
Interpretation:
Design systems with the understanding that anomalies can happen. Ensure that your Lambdas can handle identical requests without negative consequences.
Implement idempotency and retry logic in your functions, using Step Functions for effective handling of retries and error management.
Conclusion
AWS possesses a wealth of knowledge regarding serverless architecture. It’s wise to keep these design principles in mind when creating serverless solutions.
The goal is to build systems that are efficient, reliable, and cost-effective. By following AWS's serverless design principles, you can achieve this.
Remember to maintain focus, keep functions concise, design for concurrency, and orchestrate with managed services while preparing for potential failures.
Embracing serverless architecture may seem daunting, but with practice, it becomes more manageable. A skilled solutions architect simplifies complex challenges, while an exceptional architect turns intricate problems into straightforward solutions.
Strive for excellence and utilize the tools as intended.
Cheers!