Cluster registry

On a multi-cluster platform, the question "which clusters exist, where, at which version, which environment" must have a single answer: a cluster registry (inventory). In Argo CD, clusters are kept as labelled Secrets; the ApplicationSet's cluster generator deploys by these labels:

apiVersion: v1
kind: Secret
metadata:
  name: uretim-tr
  namespace: argocd
  labels:
    argocd.argoproj.io/secret-type: cluster
    ortam: uretim
    bolge: tr
stringData:
  name: uretim-tr
  server: https://tr.k8s.sirket.com

The ApplicationSet cluster generator produces an Application for each registered cluster matching the labels:

spec:
  generators:
    - clusters:
        selector:
          matchLabels:
            ortam: uretim
  template:
    metadata:
      name: 'magaza-{{name}}'
    spec:
      destination:
        server: '{{server}}'
        namespace: magaza

That way which application runs on which clusters is documented in Git and in the labels.