How to fix sync operation failed in Kubernetes

View detailed sync logs in ArgoCD UI by clicking Application > Sync > View logs. Look for the exact error message that caused the failure. The logs will show which resource failed and why.

Ensure all manifest YAML is valid:

kubectl apply -f manifest.yaml --dry-run=client

Look for indentation errors, missing colons, or invalid field names.

If sync fails with "no matches for kind", the CRD is not installed:

kubectl get crd
kubectl apply -f crd-manifest.yaml

Install the CRD before deploying resources using it.

Verify ArgoCD has permission to create the resource type:

kubectl auth can-i create deployments --as=system:serviceaccount:argocd:argocd-application-controller
kubectl auth can-i create customresources --as=system:serviceaccount:argocd:argocd-application-controller

If using remote cluster, verify connectivity:

kubectl get cluster
argocd cluster get

Ensure the cluster URL and credentials are correct.

If sync fails with "already exists", check if another application owns the resource:

kubectl get <resource> -o yaml | grep -A 2 "ownerReferences"

Either remove the conflicting resource or use ArgoCD to manage both.

If webhooks are rejecting resources, check webhook logs:

kubectl logs -l app=validation-webhook -n webhook-namespace

Adjust resource specifications to meet webhook validation rules.

Extract individual resources from your Application and apply them manually:

kubectl apply -f single-resource.yaml

This helps identify which specific resource is causing the failure.