Sync Failures from Resource Validation Errors
warningKubernetes rejects ArgoCD sync operations due to invalid resource definitions (names too long, invalid labels, missing required fields), causing deployment failures that require manual intervention.
Monitor for applications stuck in 'SyncFailed' status. Check argocd_app_sync_total with status=failed and argocd-application-controller logs for validation error patterns like 'name too long', 'invalid label', 'missing required field'. Failed syncs without infrastructure issues indicate validation problems.
Run dry-run validation before pushing to Git: argocd app sync myapp --dry-run or kubectl apply --dry-run=server. Fix common validation issues: resource names under 63 chars, label values matching [a-z0-9A-Z-_.] regex, include required fields like spec.selector for Deployments. Implement pre-commit hooks or CI validation to catch issues before ArgoCD sees them.