This chapter describes the practices for setting up a simple multitier application in Kubernetes. The application consists of a simple web application and a database.
Though this might not be the most complicated application, it is a good place to start to orient to managing an application in Kubernetes.
Application Overview
The application that we will use for our sample isn’t particularly complex. It’s a simple
journal service that stores its data in a Redis backend. It has a separate static file server using NGINX. It presents two web paths on a single
URL. The paths are one for the journal’s RESTful application programming interface (API), https://my-host.io/api, and a file server on the main URL, https://my-host.io. It uses the Let’s Encrypt service for managing Secure Sockets Layer (SSL) certificates. Figure 1-1 presents a diagram of the application. Throughout this chapter, we build up this application, first using YAML configuration files and then Helm charts.
Figure 1-1. An application diagram
Managing Configuration Files
Before we get into the details of how to construct this application in Kubernetes, it is worth discussing how we manage the configurations themselves. With Kubernetes, everything is represented declaratively. This means that you write down the desired state of the application in the cluster (generally in YAML ...
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