Function Versioning and Aliases in AWS Lambda: A comprehensive guide

As part of the AWS Solution Architect exam, understanding the concepts of Function Versioning and Aliases in AWS Lambda is imperative.

Why Function Versioning and Aliases are important: They offer the ability to seamlessly manage and invoke different versions of a function, enabling easy rollback, code testing, and staged deployment.

What are Function Versioning and Aliases: Function Versioning is a feature in AWS Lambda which allows you to manage different versions of a Lambda function. An Alias, on the other hand, is a pointer to a specific Lambda function version.

How they work: When you upload your code, AWS Lambda creates an initial version. For subsequent updates, you can create a new version which is an immutable snapshot of the code and configuration. Aliases help in routing traffic to different versions and can be accordingly updated to point to new versions.

Answering Exam Questions: Adhere to the basic principles of Aliases and Versions. Recognize that aliases allow you to direct incoming requests to different versions, and not all versions need to be available live; you can use versions to test and validate your code before updating the alias.

Exam Tips: Remember that a new version only gets created when you publish it - Lambda doesn't create versions automatically. Also, each version has its separate ARN. Comprehend that aliases can point to different versions and can be changed at any time. Understanding their organized, cohesive relationship can steer you towards the right answer in the exam.