userarn:

 mapUsers: |
 - userarn: arn:aws:iam::XXXXXXXXXXXX:user/your-aws-user
   username: your-k8s-new-user-with-master-privileges
   groups:
     - system:masters

mapRoles: |
 - rolearn: arn:aws:iam::XXXXXXXXXXXX:role/your-aws-role
   username: your-new-k8s-user-with-master
   groups:
     - system:masters

AWS IAM Authenticator for Kubernetes: aws-auth, kubectl edit -n kube-system configmap/aws-auth, eksctl create iamidentitymapping, mapUsers:, mapRoles:, mapAccounts: