Introduction

This repository is used to manage commit pins to enable promotion of changes across clusters. The repo retrieves the application objects from the cluster-config repository and then patches them to use specific commit hashes or tags to "pin" the application to a specific revision.

To manage promotions the pins can be updated on a cluster-by-cluster basis to manage the revisions.

How it Works

We are using ACM to manage the bootstrap process for new clusters, ACM has a policy that deploys the OpenShift GitOps operator plus a bootstrap application for a specific cluster. This bootstrap application points to a cluster specific folder under bootstrap/overlays that contains the commit pins for that cluster.

The kustomization for each cluster loads the configuration from the matching path in the cluster-config repository, using a kustomize remote reference, and patches the target revision in the Argo CD Applications for specific pins. In the cluster-config repo we label the applications with a repo label so we can have kustomize match the pins on a per repo basis.

Diagramming the flow, it looks like this:

ACM Policy (acm-hub-bootstrap HEAD)
     ↓
Cluster Config Pins (cluster-config-pins HEAD)
     ↓
Cluster Config (cluster-config TAG)