Book Image

Building Enterprise JavaScript Applications

By : Daniel Li
Book Image

Building Enterprise JavaScript Applications

By: Daniel Li

Overview of this book

With the over-abundance of tools in the JavaScript ecosystem, it's easy to feel lost. Build tools, package managers, loaders, bundlers, linters, compilers, transpilers, typecheckers - how do you make sense of it all? In this book, we will build a simple API and React application from scratch. We begin by setting up our development environment using Git, yarn, Babel, and ESLint. Then, we will use Express, Elasticsearch and JSON Web Tokens (JWTs) to build a stateless API service. For the front-end, we will use React, Redux, and Webpack. A central theme in the book is maintaining code quality. As such, we will enforce a Test-Driven Development (TDD) process using Selenium, Cucumber, Mocha, Sinon, and Istanbul. As we progress through the book, the focus will shift towards automation and infrastructure. You will learn to work with Continuous Integration (CI) servers like Jenkins, deploying services inside Docker containers, and run them on Kubernetes. By following this book, you would gain the skills needed to build robust, production-ready applications.
Table of Contents (26 chapters)
Title Page
Copyright and Credits
Packt Upsell
Free Chapter
The Importance of Good Code

Understanding high-level Kubernetes objects

The more observant of you might have noticed the following output after you ran kubectl:

deployment.apps "elasticsearch" created

When we run kubectl run, Kubernetes does not create a Pod directly; instead, Kubernetes automatically creates a Deployment Object that will manage the Pod for us. Therefore, the following two commands are functionally equivalent:

$ kubectl run <name> --image=<image>
$ kubectl create deployment <name> --image=<image>

To demonstrate this, you can see a list of active Deployments using kubectl get deployments:

$ kubectl get deployments
elasticsearch   1         1         1            1           2s

The benefit of using a Deployment object is that it will manage the Pods under its control. This means that if the Pod fails, the Deployment will automatically restart the Pod for us.

Generally, we should not imperatively instruct Kubernetes to create...