What Is Argo CD? A GitOps Controller for Kubernetes
Argo CD is a Kubernetes-native GitOps controller that continuously syncs your cluster to the manifests declared in a Git repository.
Argo CD implements the GitOps model concretely for Kubernetes. You point it at a repo of manifests (plain YAML, Helm, or Kustomize) and define Applications; Argo CD compares the repo to the live cluster, shows the diff, and syncs them. It gives GitOps a UI, an API, and clear sync status.
The Application object
An Argo CD Application links a source (a repo path, branch, and tooling like Helm) to a destination (a cluster and namespace). Argo CD then keeps that destination matching that source.
Sync and drift detection
Argo CD continuously compares desired state in Git against live state. It reports each Application as Synced or OutOfSync and can auto-sync changes or wait for manual approval. Manual cluster edits show up as drift.
Health and rollbacks
- It surfaces resource health (e.g. Deployment availability).
- It can self-heal by reverting drift back to Git.
- Rolling back is selecting a previous Git revision to sync to.
The visibility advantage
Beyond reconciliation, Argo CD’s dashboard shows exactly what is deployed, how it differs from Git, and the health of each piece - turning "what is actually running?" into a glance.
Argo CD in the pipeline
CI builds and pushes an image and commits the new tag or digest to the manifest repo. Argo CD detects the commit and syncs the cluster - the CD half of a GitOps pipeline, cleanly separated from CI.
Key takeaways
- Argo CD is a Kubernetes GitOps controller that syncs clusters to Git.
- Applications map a Git source to a cluster destination; it detects drift.
- CI commits the new image to Git; Argo CD reconciles the rollout.