Book Image

Scala Microservices

By : Selvam Palanimalai, Jatin Puri
Book Image

Scala Microservices

By: Selvam Palanimalai, Jatin Puri

Overview of this book

<p>In this book we will learn what it takes to build great applications using Microservices, the pitfalls associated with such a design and the techniques to avoid them. </p><p>We learn to build highly performant applications using Play Framework. You will understand the importance of writing code that is asynchronous and nonblocking and how Play leverages this paradigm for higher throughput. The book introduces Reactive Manifesto and uses Lagom Framework to implement the suggested paradigms. Lagom teaches us to: build applications that are scalable and resilient to failures, and solves problems faced with microservices like service gateway, service discovery, communication and so on. Message Passing is used as a means to achieve resilience and CQRS with Event Sourcing helps us in modelling data for highly interactive applications. </p><p>The book also shares effective development processes for large teams by using good version control workflow, continuous integration and deployment strategies. We introduce Docker containers and Kubernetes orchestrator. Finally, we look at end to end deployment of a set of scala microservices in kubernetes with load balancing, service discovery and rolling deployments. </p><p></p>
Table of Contents (12 chapters)

K8s configurations

Now that we have docker images for each individual application and we have deployment topology figured out, it is time to write actual kubernetes configurations.

The exercise in the previous section helped us plan the number of containers per service to handle our traffic.

Before we start writing our configurations, it is always good to come up with naming conventions. We will realize that soon, as there will be too many things to name. Certain conventions that we will adopt in this example are as follows:

  • Any resource created in k8s will have a name prefixed with shorthand for scalamicroservices (sm-). This is essential to distinguish between your resources and system-generated resources and also resources from other users of the cluster.
  • Decide on a tool to apply changes to kubernetes, and stick to it for consistency-- Kubectl or REST API, not both. We will...