In the previous chapters, you started to learn how to build and deploy the configuration needed to run different applications on your Kubernetes cluster.
Once you move beyond deploying the simplest of applications, you will discover that your applications often have one or more components that work in unison. For example, you might have a web application that displays information from a database that also uses a scheduled job to update that information on a regular basis. In order for this application to function correctly, both of these components need to be deployed and functioning correctly. Furthermore, these two components likely share some configuration, such as credentials for the backend database.
One other problem we might encounter when deploying applications to our Kubernetes cluster is one of reusability. Perhaps we need to run...