GitOps

In the article Install GitOps to the cluster OpenShift GitOps is deployed using a shell script. This should be the very first installation and the only deployment that is done manually on a cluster. This procedure automatically installs the so-called App-of-Apps named Argo CD Resources Manager which is responsible for all further Argo CD Applications and ApplicationSets. No other configuration should be done manually if possible.

This article will demonstrate how to configure the App-of-Apps in an easy and declarative way, using ApplicationSet mainly.

„If it is not in GitOps, it does not exist“ - is a mantra I hear quite often and also try to practice at customer engagements. The idea is to have Git as the only source of truth on what happens inside the environment. That said, Everything as Code is a practice that treats every aspect of the system as a code. Storing this code in Git provides a shared understanding, traceability and repeatability of changes.

While there are many articles about how to get GitOps into the deployment process of applications, this one rather sets the focus on the cluster configuration and tasks system administrators usually have to do.

Installing and configuring Quay Enterprise using a GitOps approach is not as easy as it sounds. On the one hand, the operator is deployed easily, on the other hand, the configuration of Quay is quite tough to do in a declarative way and syntax rules must be strictly followed.

In this article, I am trying to explain how I solved this issue by using a Kubernetes Job and a Helm Chart.

„If it is not in GitOps, it does not exist“ - However, managing objects partially only by Gitops was always an issue, since ArgoCD would like to manage the whole object. For example, when you tried to work with node labels and would like to manage them via Gitops, you would need to put the whole node object into ArgoCD. This is impractical since the node object is very complex and typically managed by the cluster. There were 3rd party solutions (like the patch operator), that helped with this issue.

However, with the Kubernetes feature Server-Side Apply this problem is solved. Read further to see a working example of this feature.

Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. GitOps itself uses Git pull request to manager infrastructure and application configuration.