Note_Tech

All technological notes.

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Argocd: App of Apps

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• Argocd: App of Apps
  • App of Apps
    • vs applicationset

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App of Apps

• App of Apps
  • a hierarchical GitOps approach where a single “root” or “parent” application is used to declaratively manage and deploy multiple other “child” Argo CD applications.
• Options
  • use the root app to track the directory recursively that stores manifests of all other apps.
    • Any new app added to the tracked directory can be synced by ArgoCD directly.
  • use root app to track helm chart that include all other apps.
    • Adding new apps will be within the helm chart , then it can be synced by ArgoCD directly

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• Example: directory of apps

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  labels:
    app.kubernetes.io/name: root-app
    name: root-app
    namespace: argocd
spec:
  project: default
  destination:
    namespace: argocd
    server: https://kubernetes.default.svc
  source:
    path: app-of-apps
    repoURL: https://github.com/mabusaa/argocd-course-app-of-apps.git
    targetRevision: main
    directory:
      recurse: true # monitor recursively
  syncPolicy:
    automated: {}

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• Example: helm chart

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  labels:
    app.kubernetes.io/name: root-app-helm-approach
    name: root-app-helm-approach
    namespace: argocd
spec:
  project: default
  destination:
    namespace: argocd
    server: https://kubernetes.default.svc
  source:
    repoURL: https://github.com/mabusaa/argocd-course-app-of-apps.git
    targetRevision: main
    path: apps-helm-chart/apps
  syncPolicy:
    automated: {}

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vs applicationset

• Both are Argo CD patterns for managing multiple applications
  • App-of-apps is a manual, declarative “parent-child” approach good for fixed, complex structures
  • ApplicationSet is a dynamic, automated controller designed for scaling across many clusters or repositories using generators.
• Use App-of-Apps:
  • When need strict synchronization ordering (Sync Waves), managing a small, fixed set of core infra apps, or prefer a straightforward “YAML-only” approach.
• Use ApplicationSet:
  • When needs to manage tens or hundreds of clusters, need to automatically create apps based on Git directory structures, or require per-app configuration via templating.
• Combine Them:
  • Many organizations use ApplicationSets to manage multiple “App-of-apps” structures, providing the best of both worlds—dynamic generation with structured, ordered deployments.