Using role in aws-auth config-map - amazon-web-services

Question

I'm using this terraform module to create eks cluster: https://github.com/terraform-aws-modules/terraform-aws-eks
Then I create an additional role and added to map_roles input similar to the example in the repo
(my role is to use CloudWatch)
{
rolearn = "arn:aws:iam::66666666666:role/role1"
username = "role1"
groups = ["system:masters"]
}
I can verify that the role is added to the aws-auth config map together with a role created by the module.
I got this error when the app trying to use CloudWatch:
User: arn:aws:sts::xxx:assumed-role/yyy/zzz is not authorized to perform: logs:DescribeLogGroups on resource: arn:aws:logs:xxx:yyy:log-group::log-stream
the User arn in the error message has the yyy part match the role arn created by the module. So I thought I'm using the wrong role? if so how can I choose the correct credential? (I'm using .NETcore, create AmazonCloudWatchLogsClient without specify any credential)
When I manually edit that role and add the log's permission, the app works. Not sure if it's the right way, if so how can I add the permission in terraforming?

Answer 1

I ended up pulling the eks module to local and add more policies to the existing role:
resource "aws_iam_policy" "my_new_policy" {
name_prefix = "eks-worker-my_new_policy-${aws_eks_cluster.this.name}"
description = "EKS worker node my_new_policy policy for cluster ${aws_eks_cluster.this.name}"
policy = data.aws_iam_policy_document.my_new_policy.json
path = var.iam_path
}
data "aws_iam_policy_document" "my_new_policy" {
statement {
sid = "my_new_policy"
effect = "Allow"
actions = [
"logs:DescribeLogGroups"
]
resources = ["*"]
}
}