Skip to main content

Create an Application

Table of Contents​

  1. Via the Web interface
  2. Via the CLI
  3. Via declarative YAML
  4. With Helm
  5. With Kustomize
  6. Hands-on exercises

1 - Via the Web interface​

Steps​

  1. Open the Argo CD UI (https://localhost:8080)
  2. Click + NEW APP
  3. Fill in the form:
FieldValue
Application Nameguestbook
Projectdefault
Sync PolicyManual
Repository URLhttps://github.com/argoproj/argocd-example-apps.git
Pathguestbook
Cluster URLhttps://kubernetes.default.svc
Namespacedefault
  1. Click CREATE
  2. Click SYNC to deploy

Workflow snapshot​

🔝 Back to table of contents​

2 - Via the CLI​

Create an application​

# Application simple
argocd app create guestbook \
  --repo https://github.com/argoproj/argocd-example-apps.git \
  --path guestbook \
  --dest-server https://kubernetes.default.svc \
  --dest-namespace default

# Vérifier
argocd app list

# Synchroniser
argocd app sync guestbook

Common options​

# Avec auto-sync
argocd app create my-app \
  --repo https://github.com/org/gitops.git \
  --path apps/my-app \
  --dest-server https://kubernetes.default.svc \
  --dest-namespace production \
  --sync-policy automated \
  --auto-prune \
  --self-heal

# Avec une branche spécifique
argocd app create my-app \
  --revision main \
  ...

# Avec un tag
argocd app create my-app \
  --revision v1.2.3 \
  ...

Useful commands​

# Voir le détail
argocd app get guestbook

# Voir les ressources
argocd app resources guestbook

# Voir l'historique
argocd app history guestbook

# Supprimer
argocd app delete guestbook

🔝 Back to table of contents​

3 - Via declarative YAML​

Basic Application​

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: guestbook
  namespace: argocd
spec:
  project: default
  
  source:
    repoURL: https://github.com/argoproj/argocd-example-apps.git
    targetRevision: HEAD
    path: guestbook
  
  destination:
    server: https://kubernetes.default.svc
    namespace: default

Application with Sync Policy​

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app
  namespace: argocd
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default
  
  source:
    repoURL: https://github.com/org/gitops.git
    targetRevision: main
    path: apps/my-app
  
  destination:
    server: https://kubernetes.default.svc
    namespace: production
  
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true
      - PruneLast=true

Apply​

kubectl apply -f application.yaml

Best practices​

metadata:
  # Finalizer pour cleanup propre
  finalizers:
    - resources-finalizer.argocd.argoproj.io
  
  # Labels pour organisation
  labels:
    app.kubernetes.io/name: my-app
    team: backend
    env: production

🔝 Back to table of contents​

4 - With Helm​

From a Helm repository​

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: nginx
  namespace: argocd
spec:
  project: default
  
  source:
    repoURL: https://charts.bitnami.com/bitnami
    chart: nginx
    targetRevision: 15.0.0
    helm:
      values: |
        replicaCount: 3
        service:
          type: ClusterIP
        resources:
          requests:
            memory: 128Mi
            cpu: 100m
  
  destination:
    server: https://kubernetes.default.svc
    namespace: web

From a Git repo containing the chart​

spec:
  source:
    repoURL: https://github.com/org/gitops.git
    path: charts/my-app
    targetRevision: HEAD
    helm:
      valueFiles:
        - values.yaml
        - values-prod.yaml
      parameters:
        - name: image.tag
          value: v1.2.3

Helm with external values​

spec:
  source:
    repoURL: https://github.com/org/gitops.git
    path: charts/my-app
    helm:
      valueFiles:
        - values.yaml
        # Fichier depuis un autre path
        - $values/environments/prod/values.yaml
  sources:
    - repoURL: https://github.com/org/config.git
      ref: values

🔝 Back to table of contents​

5 - With Kustomize​

Typical structure​

apps/my-app/
├── base/
│   ├── kustomization.yaml
│   ├── deployment.yaml
│   └── service.yaml
└── overlays/
    ├── dev/
    │   └── kustomization.yaml
    └── prod/
        └── kustomization.yaml

Kustomize Application​

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app-prod
  namespace: argocd
spec:
  project: default
  
  source:
    repoURL: https://github.com/org/gitops.git
    path: apps/my-app/overlays/prod
    targetRevision: HEAD
    kustomize:
      images:
        - name: my-app
          newTag: v1.2.3
  
  destination:
    server: https://kubernetes.default.svc
    namespace: production

Image overrides​

spec:
  source:
    kustomize:
      images:
        - name: nginx
          newName: my-registry/nginx
          newTag: custom-tag
      namePrefix: prod-
      nameSuffix: -v2
      commonLabels:
        env: production

🔝 Back to table of contents​

6 - Hands-on exercises​

Exercise 1: Deploy guestbook​

# Créer l'application
argocd app create guestbook \
  --repo https://github.com/argoproj/argocd-example-apps.git \
  --path guestbook \
  --dest-server https://kubernetes.default.svc \
  --dest-namespace default

# Synchroniser
argocd app sync guestbook

# Vérifier
kubectl get pods -n default
argocd app get guestbook

Exercise 2: Deploy with YAML​

# my-app.yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: helm-guestbook
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/argoproj/argocd-example-apps.git
    path: helm-guestbook
    targetRevision: HEAD
  destination:
    server: https://kubernetes.default.svc
    namespace: default
  syncPolicy:
    automated:
      prune: true
kubectl apply -f my-app.yaml

Quiz​

Q1. What is the difference between path and chart in source?

Answer
  • path: Path to a folder in a Git repo
  • chart: Name of a chart in a Helm repository

You use path for local manifests (YAML, Kustomize, local chart) and chart for charts from a Helm registry.

🔝 Back to table of contents​

Key takeaways​

  • 3 methods: UI, CLI, declarative YAML
  • Always specify source and destination
  • Helm: registry repoURL + chart + version
  • Kustomize: path to the overlay
  • Use labels for organization

← Previous chapter | Next chapter: Sync Strategies →