How to set up GitOps with Argo CD

What and why

GitOps treats a Git repository as the single source of truth for infrastructure and applications. Argo CD is a Kubernetes controller that continuously compares the cluster to Git and reconciles differences. This tutorial deploys an app from Git and watches Argo CD heal drift.

Prerequisites

• A running Kubernetes cluster.
• kubectl configured to reach it.
• A Git repository containing Kubernetes manifests.

Steps

1. Install Argo CD

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

This installs the controller, repo server, and API server.

2. Access the API and UI

kubectl port-forward svc/argocd-server -n argocd 8080:443

Log in with the admin user; the initial password is stored in a secret named argocd-initial-admin-secret.

3. Prepare a Git repo of manifests

Put your Deployment and Service YAML under a path such as apps/web/. This path is what Argo CD will track.

4. Create an Application

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: web
  namespace: argocd
spec:
  source:
    repoURL: https://github.com/acme/manifests
    path: apps/web
    targetRevision: main
  destination:
    server: https://kubernetes.default.svc
    namespace: web

Apply it with kubectl apply -f.

5. Enable automated sync

  syncPolicy:
    automated:
      prune: true
      selfHeal: true

selfHeal reverts manual cluster changes; prune removes resources deleted from Git.

Verification

In the UI the Application should report Synced and Healthy. Manually edit the live Deployment with kubectl scale. Within moments Argo CD detects drift and restores the Git-defined value, proving self-healing.

Next Steps

Manage many apps with an app-of-apps pattern. Combine with Helm or Kustomize for templating. Restrict who can change manifests via repository review rules, since Git access now equals deploy access.