How to install and deploy an application with Argo CD on a Kubernetes cluster?

End-to-End Deployment Workflow

Deploying an application with Argo CD involves installing the control plane, configuring access to the API server, linking a Git repository, and defining an Application resource that maps the repository state to the cluster state.

Assumptions and Uncertainty

The following steps assume a Kubernetes cluster version 1.19+ and that kubectl is configured for the target context. While the stable manifest URL is commonly used, it may point to the latest release; pinning to a specific version is recommended for production stability. Verification of RBAC permissions is required if you are deploying into a restricted environment.

1. Install Argo CD

Create a dedicated namespace and apply the official installation manifests:

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

Verify the installation by checking the server pod status:

kubectl get pods -n argocd -l app.kubernetes.io/name=argocd-server

2. Expose the API Server and Authenticate

For local development, use port-forwarding to access the UI and API. For production, use an Ingress controller with TLS.

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

Retrieve the auto-generated initial admin password:

kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath='{.data.password}' | base64 -d

Log in via the CLI (assuming the argocd binary is installed):

argocd login localhost:8080 --username admin --password <password> --insecure

3. Cluster and Repository Configuration

By default, Argo CD manages the cluster it is installed in (https://kubernetes.default.svc). To manage an external cluster, use:

argocd cluster add <context-name>

If your Git repository is private, navigate to Settings > Repositories in the UI to add your SSH or HTTPS credentials.

4. Create and Sync the Application

Define an Application manifest to link your Git source to the destination namespace. Save this as app.yaml:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/example/my-app.git
    targetRevision: HEAD
    path: manifests
  destination:
    server: https://kubernetes.default.svc
    namespace: my-app
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

Apply the manifest:

kubectl apply -f app.yaml

Verification and Rollback

• Verify: Check the UI for a Synced status and Healthy health state, or run kubectl get pods -n my-app.
• Rollback: If a deployment fails, use the CLI to revert to a previous known-good revision: argocd app rollback my-app <revision>.

Diagnostic Note: Are you using a custom CNI or Network Policy? This may require additional configuration for the Argo CD application controller to reach the target cluster API.