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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
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An EKS cluster with the Argo CD capability created
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Repository access configured (see Configure repository access)
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Target cluster registered (see Register target clusters)
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kubectlconfigured to communicate with your cluster
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: name: in-cluster namespace: default
Note
Use destination.name with the cluster name you used when registering the cluster (like in-cluster for the local cluster).
The destination.server field also works with EKS cluster ARNs, but using cluster names is recommended for better readability.
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 with values from external Git repository (multi-source pattern):
spec: sources: - repoURL: https://github.com/example/helm-charts targetRevision: main path: charts/my-app helm: valueFiles: - $values/environments/production/values.yaml - repoURL: https://github.com/example/config-repo targetRevision: main ref: values
For more information, see Helm Value Files from External Git Repository
Helm chart from ECR:
spec: source: repoURL: oci://account-id.dkr.ecr.region.amazonaws.com/repository-nametargetRevision:chart-versionchart: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-nametargetRevision: 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
Warning
Pruning will delete resources from your cluster. Use with caution in production environments.
Combined automated sync:
spec: syncPolicy: automated: prune: true selfHeal: true syncOptions: - CreateNamespace=true
Retry configuration:
Configure retry behavior for failed syncs:
spec: syncPolicy: retry: limit: 5 # Number of failed sync attempts; unlimited if less than 0 backoff: duration: 5s # Amount to back off (default unit: seconds, also supports "2m", "1h") factor: 2 # Factor to multiply the base duration after each failed retry maxDuration: 3m # Maximum amount of time allowed for the backoff strategy
This is particularly useful for resources that depend on CRDs being created first, or when working with kro instances where the CRD may not be immediately available.
Sync options
Additional sync configuration:
Create namespace if it doesn’t exist:
spec: syncPolicy: syncOptions: - CreateNamespace=true
Skip dry run for missing resources:
Useful when applying resources that depend on CRDs that don’t exist yet (like kro instances):
spec: syncPolicy: syncOptions: - SkipDryRunOnMissingResource=true
This can also be applied to specific resources using a label on the resource itself.
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:
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Sync waves - Control resource creation order with
argocd.argoproj.io/sync-waveannotations -
Sync hooks - Run jobs before or after sync with
argocd.argoproj.io/hookannotations (PreSync, PostSync, SyncFail) -
Resource health assessment - Custom health checks for application-specific resources
For details, see Sync Waves
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
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: name: 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: name: 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, the Argo CD CLI, or by updating the targetRevision in the Application spec to a previous Git commit or tag.
Using the Argo CD CLI:
argocd app rollback argocd/my-app <revision-id>
Note
When using the Argo CD CLI with the managed capability, specify applications with the namespace prefix: namespace/appname.
For more information, see argocd app rollback
Additional resources
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Working with Argo CD Projects - Organize applications with Projects for multi-tenant environments
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Use ApplicationSets - Deploy to multiple clusters with templates
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Application Specification
- Complete Application API reference -
Sync Options
- Advanced sync configuration