ArgoCD

ArgoCD is a declarative, open-source GitOps tool that keeps a Kubernetes cluster in sync with the configuration stored in a Git repository. Instead of running kubectl apply from your laptop or a CI pipeline, you commit your desired state to Git, and ArgoCD’s controller continuously watches the repository and the live cluster, applying any changes automatically or flagging them for manual approval. If someone edits a resource directly in the cluster, ArgoCD detects the drift and can revert it back to match Git. For teams running production Kubernetes, ArgoCD turns every deployment into an auditable, reversible Git commit instead of a one-off command nobody can trace back later.

How ArgoCD works

ArgoCD runs inside your Kubernetes cluster as a controller, a background process that continuously compares two things: what your Git repository says should be running, and what is actually running right now.

Here is how that loop plays out:

• Application definition: You define an Application, a custom resource that points ArgoCD at a Git repository, a path inside it, and the target cluster and namespace to deploy to.
• Manifest rendering: ArgoCD renders the actual Kubernetes YAML from whatever format you used, whether that is Helm charts, Kustomize overlays, Jsonnet, or plain manifests.
• Diffing: It compares the rendered manifests against the live state of the cluster and marks the application Synced or OutOfSync depending on whether they match.
• Syncing: When changes are detected, ArgoCD applies them to the cluster, either automatically or after a human approves the diff in the web UI.
• Drift detection: If someone changes a resource directly in the cluster outside of Git, ArgoCD flags it as drift and can automatically revert it back to the Git-defined state.

What you can build with ArgoCD

• Automated production deployment pipelines: Connect a Git repository holding your Kubernetes manifests to ArgoCD so every merged pull request rolls out to production without anyone running kubectl by hand.
• Multi-environment promotion workflows: Use separate Git branches or folders for staging and production, so promoting a release is a pull request merge instead of a manual redeploy.
• Canary and blue-green rollouts: Pair ArgoCD with Argo Rollouts to shift traffic gradually to a new version and roll back automatically if error rates spike.
• Multi-cluster fleet management: Manage dozens of Kubernetes clusters across regions or customers from a single ArgoCD instance, keeping every cluster’s configuration provably in sync with Git.
• Self-healing infrastructure: Let ArgoCD continuously reconcile drift, so a manual kubectl edit or a misconfigured autoscaler gets reverted automatically instead of silently diverging from what is documented.
• Auditable compliance trails: Give security and compliance teams a complete, timestamped history of every production change, since every deployment traces back to a specific Git commit and author.