Problem

A growing number of customers use Argo CD for managing OpenShift cluster configurations across their clusters and request guidance and recommendations from Red Hat on their use of Argo CD.

Goal

As an admin, I need guides and documentations on how to use Argo CD for managing OpenShift cluster configurations across multiple clusters:

• Installing operators from OLM
• Applying configurations to multiple clusters with deltas (kustomize)
• Modifying MachineConfigs
• Tainting nodes
• Identity Provider

Additionally, stretch goal is to link this documentation to a matching doc from the ACM team to document how a customer can seamlessly upgrade from OpenShift Pipelines to ACM based multi-cluster management. TBD - find issue in ACM team to track this collaborative doc work. 

Previous Work

Using of Argo CD for cluster configuration by Hive team:
https://github.com/openshift/openshift-gitops-examples/tree/master/argocd

Notes

• Some customers use a custom plugin for tainting nodes. The plugin first fetches the existing nodes and then applies the tainings.

Questions

• Should a custom plugin exist for patching resources on the cluster based on the patch YAML in Git where storing the complete config in Git is not feasible? Given that cluster config CRs are created by the cluster operators and not oc apply, using oc apply is not completely reliable for updating them and results in a warning. (related issue https://github.com/argoproj/argo-cd/issues/2437)

Warning: resource networks/cluster is missing the kubectl.kubernetes.io/last-applied-configuration annotation which is required by kubectl apply. kubectl apply should only be used on resources created declaratively by either kubectl create --save-config or kubectl apply. The missing annotation will be patched automatically.