Terraform-provider-kubernetes: kubernetes_cluster_role_binding & kubernetes_role_binding adding namespace when subject kind is Group

[antonosmond]

Hi

When applying a clusterrolebinding or rolebinding where the subject kind is Group, there should not be a namespace as a group is not a namespaced resource.
There's documentation here: https://kubernetes.io/docs/reference/access-authn-authz/rbac/#role-examples

Terraform Version

Terraform v0.12.16

• provider.aws v2.42.0
• provider.kubernetes v1.10.0

Affected Resource(s)

Please list the resources as a list, for example:

• kubernetes_cluster_role_binding
• kubernetes_role_binding

Terraform Configuration Files

resource "kubernetes_cluster_role_binding" "developer_cluster" {
  metadata {
    name = "company-developer"
  }
  role_ref {
    api_group = "rbac.authorization.k8s.io"
    kind      = "ClusterRole"
    name      = kubernetes_cluster_role.developer_cluster.metadata.0.name
  }
  subject {
    api_group = "rbac.authorization.k8s.io"
    kind      = "Group"
    name      = "company:developer"
  }
}

resource "kubernetes_role_binding" "developer_namespace" {
  metadata {
    name      = "company-developer"
    namespace = kubernetes_namespace.app.metadata.0.name
  }
  role_ref {
    api_group = "rbac.authorization.k8s.io"
    kind      = "ClusterRole"
    name      = kubernetes_cluster_role.developer_namespace.metadata.0.name
  }
  subject {
    api_group = "rbac.authorization.k8s.io"
    kind      = "Group"
    name      = "company:developer"
  }
}

Expected Behavior

The subject blocks of the role bindings should be created as per the config without a namespace.

Actual Behavior

The role bindings were created and the namespace field was added with a value of default.

Steps to Reproduce

Please list the steps required to reproduce the issue, for example:

1. terraform apply

[antonosmond]

If it helps I ran with log level set to TRACE and noticed this in the logs:

2019/12/17 12:46:44 [WARN] Provider "kubernetes" produced an invalid plan for kubernetes_cluster_role_binding.developer_cluster, but we are tolerating it because it is using the legacy plugin SDK.
    The following problems may be the cause of any confusing errors from downstream operations:
      - .subject[0].namespace: planned value cty.StringVal("default") does not match config value cty.NullVal(cty.String)

2019/12/17 12:46:44 [WARN] Provider "kubernetes" produced an invalid plan for kubernetes_role_binding.developer_namespace, but we are tolerating it because it is using the legacy plugin SDK.
    The following problems may be the cause of any confusing errors from downstream operations:
      - .subject[0].namespace: planned value cty.StringVal("default") does not match config value cty.NullVal(cty.String)

[Ranger-X]

Same issue. Looks related with #713.
Terraform v0.12.21

• provider.kubernetes v1.11.1

[jharshman]

Same issue, same log as above when run with TF_LOG=TRACE.

• Terraform v0.12.6
• provider.kubernetes v1.11.3

[alex-karpenko]

Same issue, unwanted namespace attribute is present for Group kind.
Terraform v0.13.4
provider.kubernetes v1.13.2

[jeffreylutz]

Hi. I discovered a work-around. Even though the documentation says that for kind: Group, namespace is a property that is not available. If you set namespace="" for kind: Group, then the resultant clusterrolebinding for kind: Group doesn't have namespace as a property, as it should.

I'm using terraform v 0.12.28

Example:

resource "kubernetes_cluster_role_binding" "cluster-superusers" {
metadata {
name = "cluster-superusers"
}
role_ref {
api_group = "rbac.authorization.k8s.io"
kind = "ClusterRole"
name = "cluster-superusers"
}
subject {
kind = "User"
name = "admin"
api_group = "rbac.authorization.k8s.io"
}
subject {
kind = "ServiceAccount"
name = "default"
namespace = "kube-system"
}
subject {
kind = "Group"
name = "system:masters"
namespace = ""
api_group = "rbac.authorization.k8s.io"
}
}

[flmmartins]

I confirm this also happens for

terraform v0.13.5
hashicorp/kubernetes v1.13.3

[mozz-lx]

The same happens when kind User is specified. Terraform tries to add an undesired namespace.

 subject {
    kind      = "User"
    name      = "myuser"
    api_group = "rbac.authorization.k8s.io"
  }

output from the plan

  ~ subject {
            api_group = "rbac.authorization.k8s.io"
            kind      = "User"
            name      = "myuser"
          + namespace = "default"
        }

my terraform informaiton.
Terraform v0.12.29
provider.kubernetes v1.13.3

[spikewang]

Still happening with the latest Kubernetes provider 2.0.2. Also confirming that the workaround works with specifying:

namespace = ""