What is ArgoCD?

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Overview

Argo CD is a declarative tool for continuous delivery, designed specifically for Kubernetes environments. It can function independently or be integrated into your broader CI/CD pipeline to deploy resources to your clusters efficiently.

Following GitOps principles, Argo CD uses your Git repository as the definitive source of truth for both infrastructure and application configurations. The desired state of your system should be defined declaratively, version-controlled in Git, and automatically applied. Argo CD makes this process seamless by continuously syncing your clusters with the configurations stored in your repository.

What is ArgoCD?

Argo CD is a GitOps-based continuous delivery tool designed for Kubernetes. It works by using Git repositories as the single source of truth for your Kubernetes resources. Argo CD continuously tracks the state of applications running in your cluster and compares them to the desired configurations stored in Git. If there are any differences, it highlights them and allows you to synchronize the live environment with the intended state, either manually or automatically through an intuitive interface.

Why use ArgoCD

  • It extends the benefits of declarative specifications and Git-based configuration management. It is the first step in achieving continuous operations on monitoring, analytics, and automation remediation. It can deploy to multiple clusters and is Enterprise-friendly( audibility, compliance, security, RBAC, SSO and a lot more.

How ArgoCD works?

  • It follows the GitOps pattern by using Git repositories as the source of truth for the desired state of the app and the target deployment envs.

Kustomize applications

Helm Charts

Ksonnet applications Jsonnet files

YAML/JSON manifests

  • It automates the synchronization of the desired application state with each of the specified target environments.

Argo CD is primarily used by DevOps engineers, platform teams, and Kubernetes administrators who manage application deployments through a GitOps-based workflow.

The GitOps model is central to Argo CD’s architecture. It treats the Git repository as the single source of truth for your application’s desired state. This means the repository should contain everything required for deployment—Kubernetes manifests, Kustomize templates, Helm charts, and configuration files. These resources declaratively define what the application should look like when successfully deployed.

ArgoCD Concepts & Terminology

Key Features of Argo CD:

  • Seamlessly deploy applications to designated environments across multiple Kubernetes clusters.
  • Compatible with a variety of configuration and templating tools, including Helm, Kustomize, Jsonnet, Ksonnet, and standard YAML files.
  • Integrates with popular Single Sign-On (SSO) providers such as OAuth2, OIDC, LDAP, SAML 2.0, GitHub, GitLab, Microsoft, and LinkedIn.
  • Supports multi-tenant setups and fine-grained Role-Based Access Control (RBAC).
  • Enables rollbacks to any previous application state stored in Git.
  • Monitors the health status of deployed resources to ensure application reliability.
  • Automatically detects and visualizes configuration drifts between live and desired states.
  • Provides built-in metrics via Prometheus for observability.
  • Maintains detailed audit logs of application events and API interactions.
  • Supports lifecycle hooks (PreSync, Sync, PostSync) for advanced deployment strategies like canary or blue/green rollouts.
  • Offers webhook support for repositories hosted on GitHub, GitLab, and Bitbucket.
  • Includes a CLI and token-based access for scripting and CI/CD pipelines.
  • Features a rich web interface for real-time insights into application status and operations.
  • Allows both automatic and manual synchronization of applications to match their Git-defined configurations.

ArgoCD Architecture

Conclusion

Argo CD is a powerful and flexible solution for teams looking to implement GitOps in their Kubernetes environments. It brings clarity, consistency, and automation to application delivery. Whether you’re managing a handful of microservices or a complex multi-cluster setup, Argo CD empowers you to deliver faster and more reliably — all while keeping Git as your single source of truth.

Mahesh Wabale
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