Production ready microservices - review
Microservices are a trend that is growing even more, recently I read the book “Production-Ready microservices” from Susan J. Fowler and it gave me insights on how to prepare or at least to have a guide go through when developing microservices. Susan says on the book that this is a guide that she whish she had when she started to standardize the microservices at user, in this sense the collection is tested in a “production” like environment and in a big size company.
Besides that, a few chapters can be taken and applied to any application, for example the reliability section, which says about process and how to document them for other developers, people on call or other teams.
Here I summarize what I found interesting and what makes sense in my context as a developer.
The splitting of a monolithic application into microservices is driven by scalability and efficiency concerns, but microservices introduce challenges of their own.
A successful, scalable microservice ecosystem requires that a stable and sophisticated infrastructure be in place. In addition, the organizational structure of a company adopting microservices must be radically changed to support microservice architecture, and the team structures that spring from this can lead to siloing and sprawl .
 also argues that microservices brings challenges, even more, he also mentions that taking the decision to go with microservices should be taken carefully.
She goes into the first chapter of the book, discussing the monolith approach of building an application, using a layered architecture (in this case a three tier with the frontend, backend and the database) and the possible strategies to scale this application due an event of an increasing demand.
On the other hand  rises the point, that the largest challenges that microservices bring is the need for standardization of the architecture. In the context of the book, it is understandable, as she was crating the process for uber and they already had a few hundreads of services running.
To say that a service is production ready, she defined eigth principles that if met, the service is considered production ready. This section dives into those criteria based on the book definition.
- Stable development life cycle
- A stable deployment process
- Stable introduction and deprecation procedures
- A reliable deployment process
- Planningm mitigating, and protecting against failures of dependencies
- Reliable routing and discovery
- Well-defined quantitative and qualitative growth scales
- Identification of resource bottlenecks and requirements
- Careful, accurate capacity planning
- Scalable handling of traffic
- The scaling of dependencies
- Scalable data storage
Fault Tolerance and Catastrophe-Preparedness
- Potential catastrophes and failure scenarios are identified and planned for
- Single points of failure are identified and resolved
- Failure detection and remediation strategies are in place
- It is tested for resiliency through code testing, load testing, and chaos testin.
- Traffic is managed carefully in preparation for failure
- Incidents and outages are handled appropriately and productivel.
- Appropriate service-level agreements (SLAs) for availability
- Proper task handling and processing
- Efficient utilization of resources
- Proper logging and tracing throughout the stack
- Well-designed dashboards that are easy to understand and accurately reflect the health of the service
- Effective, actionable alerting accompanied by runbooks
- Implementing and maintaining an on-call rotation
Documentation is the biggest challenge while developing software, at least in the projects I got involved with. There are at least three reasons for that, the first being the constant change of a feature, the second is due the lack of awareness of the team that documentation is important to keep everyone on the team on the same page, and lastly but not least it is the excuse: “it doesn’t matter”.
 defined the following bullet list to keep an eye for buidling documentation.
- Thorough, updated, and centralized documentation containing all of the relevant and essential information about the microservice
- Organizational understanding at the developer, team, and ecosystem levels
- S. Fowler, Production-Ready Microservices: Building Standardized Systems Across an Engineering Organization. O’Reilly Media, 2016.
- S. Newman, Monolith to Microservices: Sustaining Productivity While Detangling the System. O’Reilly Media, 2019.