Glossary

Application — Argo CD's core custom resource: a repo, a path, and a destination. The unit of GitOps.

app-of-apps — a parent Application whose manifests are other Applications. Bootstraps a whole cluster from one apply.

ApplicationSet — generates Applications from templates (per cluster, per environment). App-of-apps grown up.

AppProject — a boundary: which repos, clusters, and namespaces a set of Applications may use.

automated sync — Argo CD applies detected changes without human approval. Pair with prune and self-heal deliberately.

desired state — what git says should be running. The "truth" half of the comparison.

drift — the cluster disagreeing with git. Shown as OutOfSync; the thing GitOps exists to eliminate.

GitOps — the practice: git is the source of truth, software agents reconcile reality to it. Argo CD is a GitOps operator, not the idea itself.

ignoreDifferences — per-app rules telling Argo CD which live-vs-git field diffs don't count (HPA-managed replicas, injected defaults).

live state — what's actually running in the cluster. The "reality" half of the comparison.

manual sync — changes apply only when a human presses Sync. The safe default.

prune — deleting cluster resources that were removed from git. The removal half of "git is the truth."

RBAC — Argo CD's own access control (argocd-rbac-cm), separate from Kubernetes RBAC. Defines who may sync, view, or administer what.

repo server — the Argo CD component that clones git repos and renders manifests (YAML, Helm, Kustomize).

self-heal — automatically reverting hand-edits back to git state. Powerful; surprising during incidents.

sync — Argo CD applying git's desired state to the cluster.

sync wave — an annotation ordering which resources sync first (lower waves first; negative before zero).

targetRevision — the branch, tag, or commit an Application tracks. HEAD follows the branch tip.