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Create Applications

Applications represent deployments in target clusters. Each Application defines a source (Git repository) and destination (cluster and namespace). When applied, Argo CD will create the resources specified by manifests in the Git repository to the namespace in the cluster. Applications often specify workload deployments, but they can manage any Kubernetes resources available in the destination cluster.

Prerequisites

Create a basic Application

Define an Application that deploys from a Git repository:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: guestbook
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/argoproj/argocd-example-apps
    targetRevision: HEAD
    path: guestbook
  destination:
    server: arn:aws:eks:us-west-2:111122223333:cluster/my-cluster
    namespace: default

Apply the Application:

kubectl apply -f application.yaml

View the Application status:

kubectl get application guestbook -n argocd

Source configuration

Git repository:

spec:
  source:
    repoURL: https://github.com/example/my-app
    targetRevision: main
    path: kubernetes/manifests

Specific Git tag or commit:

spec:
  source:
    targetRevision: v1.2.0  # or commit SHA

Helm chart:

spec:
  source:
    repoURL: https://github.com/example/helm-charts
    targetRevision: main
    path: charts/my-app
    helm:
      valueFiles:
      - values.yaml
      parameters:
      - name: image.tag
        value: v1.2.0

Helm chart from ECR:

spec:
  source:
    repoURL: oci://account-id.dkr.ecr.region.amazonaws.com/repository-name
    targetRevision: chart-version
    chart: chart-name
      

If the Capability Role has the required ECR permissions, the repository is used directly and no Repository configuration is required. See Configure repository access for details.

Git repository from CodeCommit:

spec:
  source:
    repoURL: https://git-codecommit.region.amazonaws.com/v1/repos/repository-name
    targetRevision: main
    path: kubernetes/manifests

If the Capability Role has the required CodeCommit permissions, the repository is used directly and no Repository configuration is required. See Configure repository access for details.

Git repository from CodeConnections:

spec:
  source:
    repoURL: https://codeconnections.region.amazonaws.com/git-http/account-id/region/connection-id/owner/repository.git
    targetRevision: main
    path: kubernetes/manifests

The repository URL format is derived from the CodeConnections connection ARN. If the Capability Role has the required CodeConnections permissions and a connection is configured, the repository is used directly and no Repository configuration is required. See Configure repository access for details.

Kustomize:

spec:
  source:
    repoURL: https://github.com/example/kustomize-app
    targetRevision: main
    path: overlays/production
    kustomize:
      namePrefix: prod-

Sync policies

Control how Argo CD syncs applications.

Manual sync (default):

Applications require manual approval to sync:

spec:
  syncPolicy: {}  # No automated sync

Manually trigger sync:

kubectl patch application guestbook -n argocd \
  --type merge \
  --patch '{"operation": {"initiatedBy": {"username": "admin"}, "sync": {}}}'

Automatic sync:

Applications automatically sync when Git changes are detected:

spec:
  syncPolicy:
    automated: {}

Self-healing:

Automatically revert manual changes to the cluster:

spec:
  syncPolicy:
    automated:
      selfHeal: true

When enabled, Argo CD reverts any manual changes made directly to the cluster, ensuring Git remains the source of truth.

Pruning:

Automatically delete resources removed from Git:

spec:
  syncPolicy:
    automated:
      prune: true

Combined automated sync:

spec:
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
    - CreateNamespace=true

Sync options

Additional sync configuration:

Create namespace if it doesn’t exist:

spec:
  syncPolicy:
    syncOptions:
    - CreateNamespace=true

Validate resources before applying:

spec:
  syncPolicy:
    syncOptions:
    - Validate=true

Apply out of sync only:

spec:
  syncPolicy:
    syncOptions:
    - ApplyOutOfSyncOnly=true

Advanced sync features

Argo CD supports advanced sync features for complex deployments:

For details, see Sync Waves and Resource Hooks in the Argo CD documentation.

Ignore differences

Prevent Argo CD from syncing specific fields that are managed by other controllers (like HPA managing replicas):

spec:
  ignoreDifferences:
  - group: apps
    kind: Deployment
    jsonPointers:
    - /spec/replicas

For details on ignore patterns and field exclusions, see Diffing Customization in the Argo CD documentation.

Multi-environment deployment

Deploy the same application to multiple environments:

Development:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app-dev
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/example/my-app
    targetRevision: develop
    path: overlays/development
  destination:
    server: arn:aws:eks:us-west-2:111122223333:cluster/dev-cluster
    namespace: my-app

Production:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app-prod
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/example/my-app
    targetRevision: main
    path: overlays/production
  destination:
    server: arn:aws:eks:us-west-2:111122223333:cluster/prod-cluster
    namespace: my-app
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

Monitor and manage Applications

View Application status:

kubectl get application my-app -n argocd

Access the Argo CD UI:

Open the Argo CD UI through the EKS console to view application topology, sync status, resource health, and deployment history. See Working with Argo CD for UI access instructions.

Rollback Applications:

Rollback to a previous revision using the Argo CD UI or by updating the targetRevision in the Application spec to a previous Git commit or tag.

Additional resources