In Part 5 of this series, we validated the cluster end to end by deploying Nginx. Now let's go one step further: build a custom application's Docker image, publish it, get it running in the cluster, and explore day-to-day operations — version updates, rollback, and scalability (both manual and automatic).
As an example, we used a simple REST API (myapp.war), built with Spring Boot, purely for illustration — the process applies to any application packaged as a container image.
Building the application's Docker image
The first step is writing the application's Dockerfile. In this example, a lightweight base image (alpine) was used, with Java 11 installed to run the application:
FROM alpine
