Monolith to Microservices

Microservices Transformation

A microservices software architecture is the pinnacle of Cloud Native computing, and is relatively simple to understand when considering greenfield projects, but for most enterprise organizations it quickly brings them back around to the topic of legacy modernization, requiring a much more complex challenge of how to adapt their existing systems to this new approach.

This presentation from Linkedin offers a detailed case study, describing their approach for exactly this scenario – From a Monolith to Microservices + REST.

This describes:

• A legacy estate of Java, Servlets, JSP and Oracle databases.
• A need to support fast release iterations as far back as 2010, which ran into the core challenges associated with monolith software: Test failures, rollback difficulties and complex orchestration and dependencies between services.
• So they broke apart the codebase, adopted Continuous Delivery practices and devolved controls, implementing a decentralized code base.
• The use of Java RPC meant a proliferation of APIs made backwards compatibility a big problem, a situation they addressed by moving to Rest.li, a REST + JSON framework, key components from the Netflix suite – Apache Zookeeper for dynamic service discovery, and DECO for URN resolution to explore data graphs.

This combination formed their particular ‘Microservices Recipe’, and when you consider the role social graphs play across the Linkedin environment, how our business contacts are inter-connected and we dynamically explore our way through them, you can see how it would be an ideal design for this type of web site. Others offer very practical permutations.

In this article Flickr describe how you can utilize Github to operate a ‘Microservices Store’.

“Some of the products that we work with at Yahoo have a very granular architecture with hundreds of micro-services working together. For scenarios like this, it’s convenient to store configurations for all services in a single repository. It greatly reduces the overhead of maintaining multiple repositories. We support this use case by having multiple top-level directories, each holding configurations for one service only.”

This is a great idea when you consider Github can provide the foundation for a complete DevOps toolchain, augmented in many ways such as adding apps to support Agile practices. Similarly Sensedia propose a recipe for Legacy Modernization that defines how microservices can be utilized as an API enablement strategy.

Chandra Rajasekharaiah, Enterprise Solutions Architect at Macy’s, published this excellent deep dive analysis of the Monolith to Microservices transformation and the software engineering challenges it presents, and Anil Madan, VP of Engineering at Intuit also describes the same journey encompassing a broader perspective of platforms and organizations.

For example in this article Flickr describe how you can utilize Github to operate a ‘Microservices Store’. “Some of the products that we work with at Yahoo have a very granular architecture with hundreds of micro-services working together. For scenarios like this, it’s convenient to store configurations for all services in a single repository. It greatly reduces the overhead of maintaining multiple repositories. We support this use case by having multiple top-level directories, each holding configurations for one service only.” This is a great idea when you consider Github can provide the foundation for a complete DevOps toolchain, augmented in many ways such as adding apps to support Agile practices.