Managing IAM authentication user (ConfigMap)

Available in VPC

When creating a cluster, both the SubAccount that created the cluster and the main account are automatically set as the system:masters group within the cluster's RBAC configuration. This setting is not displayed in the cluster information or ConfigMaps. In order to give usage permissions a cluster to an IAM user, ncp-auth ConfigMap must be registered in the kube-system namespace.

Add IAM user to cluster

1. The kubectl credentials must be configured with the SubAccount user who created the cluster or the main account.
2. Create ncp-auth ConfigMap.

$ cat <<EOF | kubectl --kubeconfig $KUBE_CONFIG apply -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: ncp-auth
  namespace: kube-system
data:
  mapSubAccounts: |
    - subAccountIdNo: <iam-user-idno>
      username: <username>
      groups:
        - <groups>
EOF

3. ConfigMap's IAM user parameters are as follows:
   • subaccountIdNo: the ID of the SubAccount user to be added that can be checked on the SubAccount console
   • username: the name of the user to be mapped to the IAM user in Kubernetes
   • groups: list of groups to be mapped to users in Kubernetes For more details, see Default roles and role bindings.
4. ncp-auth You can check the list of applied users through the ncloud.com/applied-ncp-auth annotation in the ConfigMap.

$ kubectl --kubeconfig $KUBE_CONFIG -n kube-system get configmap ncp-auth -o yaml
...
metadata:
  annotations:
     ncloud.com/applied-ncp-auth: '[{"SubAccountIdNo":"<iam-user-idno>","Username":"<username>","Groups":["<groups>"]}]'
...     

5. Check if the IAM user, or the user or user group with a role mapped, is bound to a Kubernetes role by using RoleBinding or ClusterRoleBinding. For more information, see Using RBAC Authorization in the Kubernetes documents.

• Permission to view resources in all namespaces - The group name is full-access-group, and this needs to be mapped to the IAM user groups in the ncp-auth ConfigMap.

$ cat <<EOF | kubectl --kubeconfig $KUBE_CONFIG apply -f -  
apiVersion: rbac.authorization.k8s.io/v1  
kind: ClusterRole  
metadata:  
 name: full-access-clusterrole  
rules:  
- apiGroups:  
  - ""  
  resources:  
  - nodes  
  - namespaces  
  - pods  
  verbs:  
  - get  
  - list  
- apiGroups:  
  - apps  
  resources:  
  - deployments  
  - daemonsets  
  - statefulsets  
  - replicasets  
  verbs:  
  - get  
  - list  
- apiGroups:  
  - batch  
  resources:  
  - jobs  
  verbs:  
  - get  
  - list  
---  
apiVersion: rbac.authorization.k8s.io/v1  
kind: ClusterRoleBinding  
metadata:  
 name: full-access-binding  
subjects:  
- kind: Group  
  name: full-access-group  
  apiGroup: rbac.authorization.k8s.io  
roleRef:  
 kind: ClusterRole  
 name: full-access-clusterrole  
 apiGroup: rbac.authorization.k8s.io  
EOF  

• Permission to view resources for a specific namespace - As the namespace set to the file is restricted-access-group, specify the namespace you want and edit it. The group name is restricted-access-group, and this needs to be mapped to IAM user groups in the ncp-auth ConfigMap.

$ cat <<EOF | kubectl --kubeconfig $KUBE_CONFIG apply -f -  
apiVersion: rbac.authorization.k8s.io/v1  
kind: ClusterRole  
metadata:  
  name: restricted-access-clusterrole  
rules:  
- apiGroups:  
  - ""  
  resources:  
  - nodes  
  - namespaces  
  verbs:  
  - get  
  - list  
---  
apiVersion: rbac.authorization.k8s.io/v1  
kind: ClusterRoleBinding  
metadata:  
  name: restricted-access-clusterrole-binding  
subjects:  
- kind: Group  
  name: restricted-access-group  
  apiGroup: rbac.authorization.k8s.io  
roleRef:  
  kind: ClusterRole  
  name: restricted-access-clusterrole  
  apiGroup: rbac.authorization.k8s.io  
---  
apiVersion: rbac.authorization.k8s.io/v1  
kind: Role  
metadata:  
  namespace: default  
  name: restricted-access-role  
rules:  
- apiGroups:  
  - ""  
  resources:  
  - pods  
  verbs:  
  - get  
  - list  
- apiGroups:  
  - apps  
  resources:  
  - deployments  
  - daemonsets  
  - statefulsets  
  - replicasets  
  verbs:  
  - get  
  - list  
- apiGroups:  
  - batch  
  resources:  
  - jobs  
  verbs:  
  - get  
  - list  
---  
apiVersion: rbac.authorization.k8s.io/v1  
kind: RoleBinding  
metadata:  
  name: restricted-access-role-binding  
  namespace: default  
subjects:  
- kind: Group  
  name: restricted-access-group  
  apiGroup: rbac.authorization.k8s.io  
roleRef:  
  kind: Role  
  name: restricted-access-role  
  apiGroup: rbac.authorization.k8s.io  
EOF  

Authenticate all without registering them in mapSubAccounts

1. If you add the authenticateAll value to the ncp-auth ConfigMap as true, all SubAccount accounts are authenticated even if they are not added to mapSubAccounts.

$ cat <<EOF | kubectl --kubeconfig $KUBE_CONFIG apply -f -  
apiVersion: v1  
kind: ConfigMap  
metadata:  
  name: ncp-auth  
  namespace: kube-system  
data:  
  authenticateAll: "true"  
EOF  

2. Authenticated users must use RoleBinding or ClusterRoleBinding to ensure that Kubernetes users or groups are bound to a Kubernetes role in the same way as SubAccount users are added to the cluster.

Use SubAccount group as Kubernetes group

1. SubAccount users belonging to the SubAccount group will be included in the Kubernetes group to which ncp-sub-account-group: is added as a prefix.
2. An example of granting full-access-clusterrole to all users belonging to the SubAccount group called full-access is as follows:

$ cat <<EOF | kubectl --kubeconfig $KUBE_CONFIG apply -f -  
apiVersion: rbac.authorization.k8s.io/v1  
kind: ClusterRole  
metadata:  
 name: full-access-clusterrole  
rules:  
- apiGroups:  
  - ""  
  resources:  
  - nodes  
  - namespaces  
  - pods  
  verbs:  
  - get  
  - list  
- apiGroups:  
  - apps  
  resources:  
  - deployments  
  - daemonsets  
  - statefulsets  
  - replicasets  
  verbs:  
  - get  
  - list  
- apiGroups:  
  - batch  
  resources:  
  - jobs  
  verbs:  
  - get  
  - list  
---  
apiVersion: rbac.authorization.k8s.io/v1  
kind: ClusterRoleBinding  
metadata:  
 name: full-access-binding  
subjects:  
- kind: Group  
  name: ncp-sub-account-group:full-access  
  apiGroup: rbac.authorization.k8s.io  
roleRef:  
 kind: ClusterRole  
 name: full-access-clusterrole  
 apiGroup: rbac.authorization.k8s.io  
EOF