How ArgoCD Works?

ArgoCD is an open-source declarative continuous delivery (CD) tool designed to simplify and automate the deployment of applications in Kubernetes clusters. It enables users to manage and deploy their applications using Git repositories, making the process more efficient and scalable. In this article, we will delve into the workings of ArgoCD, exploring its key features, commands, and step-by-step instructions to better understand its functionality.

Understanding the Basics:

ArgoCD follows a declarative approach to continuous delivery, where the desired state of the application is defined in a Git repository. The tool then ensures that the deployed application matches this desired state, providing a reliable and consistent deployment process.

1. Installation of ArgoCD:
   To get started with ArgoCD, the first step is installation. Use the following command to install ArgoCD on your Kubernetes cluster:

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

   This command deploys ArgoCD along with its components on your Kubernetes cluster.

2. Accessing the ArgoCD Dashboard:
   Once installed, you can access the ArgoCD dashboard using the following port-forwarding command:

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

   After port forwarding, open your browser and go to http://localhost:8080. Log in with the default username and password (admin/admin).

3. Application Configuration in ArgoCD:
   ArgoCD uses Kubernetes manifests stored in a Git repository to define the desired state of applications. Create an application by specifying the Git repository URL and path to the manifests:

   argocd app create my-app --repo https://github.com/example/my-app.git --path .
   

   This command creates an application named "my-app" linked to the specified Git repository.

4. Syncing Applications:
   ArgoCD continuously monitors the Git repository for changes. To synchronize an application with its desired state, use the following command:

   argocd app sync my-app
   

   This command ensures that the deployed application matches the state defined in the Git repository.

5. Rollback in ArgoCD:
   In case of issues or errors, ArgoCD supports easy rollbacks to a previous version. Use the following command to roll back an application:

   argocd app rollback my-app
   

   This command reverts the application to the previous state defined in the Git repository.

ArgoCD simplifies and enhances the continuous delivery process for Kubernetes applications by leveraging Git repositories and a declarative approach. Its installation, dashboard access, application configuration, syncing, and rollback capabilities make it a powerful tool for managing deployments in Kubernetes environments.