ArgoCD

ArgoCD is a Kubernetes controller that continuously watches a Git repository and ensures your cluster's actual state matches what's declared in that repo. If someone manually modifies a Kubernetes resource ("drift"), ArgoCD detects it and either alerts or auto-corrects. This GitOps model makes every deployment auditable, reversible, and reproducible.

GitOps Model

The GitOps workflow:

1. Developer merges a PR that updates a Kubernetes manifest (or Helm values)
2. ArgoCD detects the change in Git (polling or webhook)
3. ArgoCD applies the diff to the cluster
4. ArgoCD reports sync status: Synced, OutOfSync, Degraded

No kubectl apply in CI pipelines, no direct cluster access needed by developers, full audit trail in Git history.

Core Concepts

• Application , ArgoCD's CRD that links a Git repo/path to a cluster namespace
• Sync , the act of applying Git state to the cluster
• Sync Policy , manual (human clicks sync) or automated (ArgoCD syncs immediately on change)
• Health Status , whether deployed resources are actually running correctly
• AppProjects , RBAC scoping: which repos can deploy to which clusters/namespaces

Source Types

ArgoCD can sync from:

• Raw Kubernetes YAML manifests
• Helm charts (with values overrides)
• Kustomize overlays
• Jsonnet
• Any tool via config management plugins

Multi-Cluster Management

One ArgoCD instance can manage multiple clusters, staging, production, different regions. ApplicationSets generate ArgoCD Applications programmatically across clusters from a single template, ideal for platform teams managing many tenant clusters.

ArgoCD vs Flux

Both implement GitOps for Kubernetes. ArgoCD has a richer UI and user-facing features; Flux is more lightweight, Kubernetes-native (uses CRDs exclusively), and has better multi-tenancy support. For teams that want a UI and easy onboarding, ArgoCD. For platform engineering teams that want a minimal controller, Flux.

Integration with CI

A common pattern: CI builds and pushes a Docker image, updates the image tag in the Helm values or manifest file in Git, and commits. ArgoCD detects the commit and deploys. CI never touches the cluster directly, it only updates Git.

Related Terms

• Helm, primary packaging format ArgoCD deploys
• Kubernetes, the platform ArgoCD manages
• Pulumi, IaC for cluster infrastructure; ArgoCD for workload delivery
• Hashicorp Vault, secrets injected into workloads that ArgoCD deploys