After a conversation with my colleague Tero Ahonen we decided to prepare a session to highlight the benefits a developer can get from Operators in general and from the Operator Framework in particular. For that session we depicted two demos: one to show how easy it is to have a Kafka cluster on OpenShift (Red Hat's Kubernetes distribution) and another one showing a custom operator that could deploy and update an application called Gramola using the Operator Lifecycle Manager (OLM). This is the repository for the latter.
Gramola is a simple application that shows a list of (musical) Events. It comprises:
- frontend: NodeJS/Angular application
- gateway: Quarkus simple API gateway
- events: Quarkus simple API
- events-database: PostgreSQL 10 Database
Here you have a screenshot showing the end result and ultimate goal of the operator.
The purpose of this repository is twofold:
- Providing a lab guide to create and upgrade an operator from scratch and using the Operator Lifecycle Manager
- Holding the code and demo script of Gramola
So you can develop your own operator to then deploy it and upgrade it using OLM (for the brave!) or just deploy and upgrade the Gramola Operator (for... also the brave!).
NOTE 1: This guide covers using OLM on Kubernetes and also on OpenShift.
NOTE 2: Some say I tend to use NOTES more than average... it's true.
This guide is divided into two parts.
In Part One you'll learn:
- How to create an operator and how to deploy version 0.0.1
- You will also learn how to evolve an operator as we'll move from version 0.0.1 to 0.0.2.
- And even more importantly how to use the Operator Lifecycle Manager (OLM) to do all this automatically.
NOTE: In order to make the Part One easier (Gramola is not complicated but it has too many moving parts) we're going to use the Golang Based Operator Tutorial as a base for this lab.
The 2nd part of the guide explains how to run a complete demonstration using the Gramola operator on Kubernetes, no need to code just enjoy deploying and upgrading Gramola. If you're using/testing OpenShift then I suggest you to run also/instead this version of the guide (the inner workings are the same but the screenshots are different).
How is this guide different to others?
- It shows you how to get it all done from zero to upgrade your operator seamlessly using the Operator Lifecycle Manager.
- It also shows you how to do this with Minikube and OpenShift.
Thanks to Tero Ahonen who pushed me (inadvertently?) to create this.
Parts of the code of this operator were borrowed from another operator coded by my colleague Madou Couliba.
Luis Arizmendi was key to start working with OLM, here the article that helped me with this subject.