Diff_customization.md

Diff Customization (Ignore Differences for Deployment Replicas)

This exercise showcases how to customize Argo CD's diffing behavior to ignore differences in the number of replicas for a Deployment resource. Follow these steps:

Solution

1. Create an Argo CD Application Declaratively Using YAML with the Following Specifications

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata: 
  name: diffing-customization-demo
  namespace: argocd
spec: 
  destination:
    namespace: diffing-customization-demo
    server: "https://kubernetes.default.svc"
  project: default
  source: 
    path: guestbook-with-sub-directories
    repoURL: "https://github.com/spy86/argocd-example-apps.git"
    targetRevision: master
    directory:
      recurse: true
  syncPolicy:
    automated: {}
    syncOptions:
      - CreateNamespace=true
  ignoreDifferences:
    - group: apps
      kind: Deployment
      jsonPointers:
        - /spec/replicas

2. Apply this Manifest with kubectl

kubectl apply -f app.yaml -n argocd

3. Verify App

kubectl get application -n argocd

4. Verify that Resources are Created in diffing-customization-demo Namespace

kubectl get all -n diffing-customization-demo

5. Scale the Deployment into 3 Replicas Using kubectl

kubectl scale deployment/guestbook-ui -n diffing-customization-demo --replicas=3

6. Retrieve the admin password for ArgoCD WebUI

kubectl port-forward svc/argocd-server -n argocd 8080:443
kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo

7. Refresh the Application in Argo CD