Deploying Applications in Kubernetes With Argo CD for Beginners

Deploying applications in Kubernetes can be challenging, especially for beginners. However, tools like Argo CD simplify the process by leveraging GitOps principles to automate and manage deployments seamlessly. In this guide, you’ll learn how to set up and use Argo CD to deploy applications in Kubernetes, step-by-step.

Whether you're new to Kubernetes or looking to streamline your deployment process, this guide is designed to help you get started with Argo CD. Plus, if you need expert assistance, ZippyOPS offers consulting, implementation, and management services for DevOps, DevSecOps, Cloud, AI Ops, Microservices, and more.

What You’ll Learn

• Installing and configuring Argo CD.

• Deploying applications using GitOps principles.

• Monitoring deployments and troubleshooting issues.

• Rolling back and managing application versions.

• Securing Argo CD for production environments.

Why Use Argo CD?

Argo CD is a declarative, GitOps-powered tool that simplifies Kubernetes application management. Here’s why it’s a game-changer:

• Declarative Management: Define your desired cluster state in Git.

• Continuous Delivery: Automate deployments with real-time synchronization.

• Version Control: Easily roll back to previous versions.

Prerequisites

Before diving in, ensure you have the following:

1. A Kubernetes cluster (use Minikube, Kind, or managed services like GKE, EKS, or AKS).

2. kubectl installed and configured to connect to your cluster.

3. A GitHub or GitLab account to host your Kubernetes manifests.

4. Basic familiarity with YAML syntax (don’t worry, this guide will help you!).

Step-by-Step Guide to Deploying Applications with Argo CD

1. Setting Up a Kubernetes Cluster

Step 1: Install Minikube
If you don’t have a cluster, use Minikube:
curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
chmod +x minikube-linux-amd64
sudo mv minikube-linux-amd64 /usr/local/bin/minikube

Step 2: Start Minikube
Run the following command:
minikube start

Step 3: Verify Cluster
Confirm the cluster is running:
kubectl cluster-info
kubectl get nodes

2. Installing Argo CD

Step 1: Create Namespace
Argo CD runs in its own namespace for isolation:
kubectl create namespace argocd

Step 2: Install Argo CD
Apply the official manifests:
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

Step 3: Verify Installation
Check the Argo CD pods:
kubectl get pods -n argocd

3. Accessing the Argo CD UI

Step 1: Expose Argo CD
Expose the argocd-server to your local machine:
kubectl port-forward svc/argocd-server -n argocd 8080:443

Step 2: Retrieve Admin Credentials
Fetch the default admin password:
kubectl get secret argocd-initial-admin-secret -n argocd -o jsonpath="{.data.password}" | base64 -d

Step 3: Login to UI

1. Open https://localhost:8080 in your browser.

2. Log in with:

   • Username: admin

   • Password: Retrieved in the previous step.

4. Connecting Argo CD to Your Git Repository

Step 1: Prepare a Git Repository

1. Create a Git repository (e.g., on GitHub).

2. Add your Kubernetes manifests. Here’s a sample deployment.yaml:
   apiVersion: apps/v1
   kind: Deployment
   metadata:
   name: nginx-deployment
   labels:
   app: nginx
   spec:
   replicas: 2
   selector:
   matchLabels:
   app: nginx
   template:
   metadata:
   labels:
   app: nginx
   spec:
   containers:
   - name: nginx
   image: nginx:1.19
   ports:
   - containerPort: 80

Step 2: Add Repository to Argo CD
From the UI:

1. Navigate to Settings > Repositories.

2. Add your Git repository URL and authentication details.

Or, use the CLI:
argocd repo add --username  --password 

5. Deploying Your First Application

Step 1: Create an Application
In the Argo CD UI:

1. Click New App.

2. Fill in the details:

   • App Name: nginx-app

   • Project: default

   • Repository URL: Your Git repo URL

   • Path: Path to deployment.yaml

   • Cluster URL: https://kubernetes.default.svc

   • Namespace: default

Step 2: Sync the Application
After creating the app:

1. Click Sync in the Argo CD UI.

2. Watch as the app deploys to your Kubernetes cluster.

6. Automating Deployments

Step 1: Enable Auto-Sync
Enable continuous synchronization:
argocd app set nginx-app --sync-policy automated

Step 2: Test Changes

1. Modify the deployment.yaml in Git.

2. Push changes to the repository.

3. Argo CD will detect the changes and automatically sync them to the cluster.

7. Monitoring and Troubleshooting

Step 1: Monitor Application Health
In the UI, check:

• Health: Indicates if the application is running as expected.

• Sync Status: Ensures the cluster state matches Git.

Step 2: View Logs
If something goes wrong:
kubectl logs -n argocd

Step 3: Roll Back Changes
Roll back to a previous state:
argocd app rollback nginx-app 

8. Securing Argo CD

Step 1: Change Default Admin Password
Change the default admin password:
argocd account update-password

Step 2: Integrate SSO
For production environments, integrate with Single Sign-On (SSO) solutions like GitHub or LDAP.

GitOps Best Practices

1. Branch Strategies: Use separate branches for development, staging, and production.

2. Code Reviews: Enforce peer reviews for manifest changes.

3. Audit Logs: Regularly review Argo CD logs for compliance and debugging.

Conclusion

Argo CD is a powerful yet beginner-friendly tool for managing Kubernetes deployments using GitOps principles. By following this guide, you’ll be able to deploy, monitor, and manage applications efficiently.

If you’re looking for expert assistance, ZippyOPS provides consulting, implementation, and management services for DevOps, DevSecOps, Cloud, AI Ops, Microservices, and more. Explore their services, products, and solutions. For demo videos, check out their YouTube Playlist.

If this seems interesting, email them at [email protected] for a call.

By mastering Argo CD and GitOps, you’re well on your way to becoming a Kubernetes deployment