Control access using Microsoft Entra ID and Kubernetes RBAC for Windows Server
Applies to: AKS on Azure Stack HCI 22H2, AKS on Windows Server
Azure Kubernetes Service (AKS) can be configured to use Microsoft Entra ID for user authentication. In this configuration, you sign in to a Kubernetes cluster using a Microsoft Entra authentication token. Once authenticated, you can use the built-in Kubernetes role-based access control (Kubernetes RBAC) to manage access to namespaces and cluster resources based on a user's identity or group membership.
This article describes how to control access using Kubernetes RBAC in a Kubernetes cluster based on Microsoft Entra group membership in AKS Arc. You create a demo group and users in Microsoft Entra ID. Then, you create roles and role bindings in the cluster to grant the appropriate permissions to create and view resources.
Prerequisites
Before you set up Kubernetes RBAC using Microsoft Entra ID, you need the following prerequisites:
- A Kubernetes cluster created in AKS Arc. If you need to set up your cluster, see the instructions for using Windows Admin Center or PowerShell to deploy AKS.
- Azure Arc connection. You must have an Azure Arc connection to your Kubernetes cluster. For information about enabling Azure Arc, see Connect an Azure Kubernetes Service on Azure Stack HCI cluster to Azure Arc-enabled Kubernetes.
- You need access to the following command-line tools:
- Azure CLI and the connectedk8s extension. Azure CLI is a set of commands used to create and manage Azure resources. To check whether you have the Azure CLI, open a command line tool, and type:
az -v
. Also, install the connectedk8s extension in order to open a channel to your Kubernetes cluster. For installation instructions, see How to install Azure CLI. - Kubectl. This Kubernetes command-line tool enables you to run commands targeting your Kubernetes clusters. To check whether you installed kubectl, open a command prompt and type:
kubectl version --client
. Make sure your kubectl client version is at least version v1.24.0. For installation instructions, see kubectl. - PowerShell and the AksHci PowerShell module. PowerShell is a cross-platform task automation solution comprised of a command-line shell, a scripting language, and a configuration management framework. If you installed AKS Arc, you have access to the AksHci PowerShell module.
- To access the Kubernetes cluster from anywhere with a proxy mode using
az connectedk8s proxy
command, you need the Microsoft.Kubernetes/connectedClusters/listClusterUserCredential/action, which is included in the Azure Arc-enabled Kubernetes Cluster User role permission. Meanwhile, you need to verify that the agents and the machine performing the onboarding process meet the network requirements in Azure Arc-enabled Kubernetes network requirements.
- Azure CLI and the connectedk8s extension. Azure CLI is a set of commands used to create and manage Azure resources. To check whether you have the Azure CLI, open a command line tool, and type:
Optional first steps
If you don't already have a Microsoft Entra group that contains members, you might want to create a group and add some members, so that you can follow the instructions in this article.
To demonstrate working with Microsoft Entra ID and Kubernetes RBAC, you can create a Microsoft Entra group for application developers that can be used to show how Kubernetes RBAC and Microsoft Entra ID control access to cluster resources. In production environments, you can use existing users and groups within a Microsoft Entra tenant.
Create a demo group in Microsoft Entra ID
First, create the group in Microsoft Entra ID in your tenant for the application developers using the az ad group create
command. The following example prompts you to sign into your Azure tenant and then creates a group named appdev:
az login
az ad group create --display-name appdev --mail-nickname appdev
Add users to your group
With the example group created in Microsoft Entra ID for application developers, add a user to the appdev
group. You use this user account to sign in to the AKS cluster and test the Kubernetes RBAC integration.
Add a user to the appdev group created in the previous section using the az ad group member add
command. If you quit your session, reconnect to Azure using az login
.
$AKSDEV_ID = az ad user create --display-name <name> --password <strongpassword> --user-principal-name <name>@contoso.onmicrosoft.com
az ad group member add --group appdev --member-id $AKSDEV_ID
Create a custom Kubernetes RBAC role binding on the AKS cluster resource for the Microsoft Entra group
Configure the AKS cluster to allow your Microsoft Entra group to access the cluster. If you want to add a group and users, see Create demo groups in Microsoft Entra ID.
Get the cluster admin credentials using the
Get-AksHciCredential
command:Get-AksHciCredential -name <name-of-your-cluster>
Create a namespace in the Kubernetes cluster using the
kubectl create namespace
command. The following example creates a namespace nameddev
:kubectl create namespace dev
In Kubernetes, Roles define the permissions to grant, and RoleBindings apply the permissions to desired users or groups. These assignments can be applied to a given namespace or across an entire cluster. For more information, see Using Kubernetes RBAC authorization.
Create a role for the dev namespace. This role grants full permissions to the namespace. In production environments, you might want to specify more granular permissions for different users or groups.
Create a file named role-dev-namespace.yaml and copy/paste the following YAML manifest:
kind: Role apiVersion: rbac.authorization.k8s.io/v1 metadata: name: dev-user-full-access namespace: dev rules: - apiGroups: ["", "extensions", "apps"] resources: ["*"] verbs: ["*"] - apiGroups: ["batch"] resources: - jobs - cronjobs verbs: ["*"]
Create the role using the
kubectl apply
command, and specify the filename of your YAML manifest:kubectl apply -f role-dev-namespace.yaml
Get the resource ID for the appdev group using the
az ad group show
command. This group is set as the subject of a RoleBinding in the next step:az ad group show --group appdev --query objectId -o tsv
The
az ad group show
command returns the value you use as thegroupObjectId
:38E5FA30-XXXX-4895-9A00-050712E3673A
Create a file named rolebinding-dev-namespace.yaml, and copy/paste the following YAML manifest. You establish the role binding that enables the appdev group to use the
role-dev-namespace
role for namespace access. On the last line, replacegroupObjectId
with the group object ID produced by theaz ad group show
command:kind: RoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata: name: dev-user-access namespace: dev roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: dev-user-full-access subjects: - kind: Group namespace: dev name: groupObjectId
Tip
If you want to create the RoleBinding for a single user, specify
kind: User
and replacegroupObjectId
with the user principal name (UPN) in the sample.Create the RoleBinding using the
kubectl apply
command and specify the filename of your YAML manifest:kubectl apply -f rolebinding-dev-namespace.yaml
rolebinding.rbac.authorization.k8s.io/dev-user-access created
Use built-in Kubernetes RBAC roles for your AKS cluster resource
Kubernetes also provides built-in user-facing roles. These built-in roles include:
- Super-user roles (cluster-admin)
- Roles intended to be granted cluster-wide using ClusterRoleBindings
- Roles intended to be granted within particular namespaces using RoleBindings (admin, edit, view)
For more information about built-in Kubernetes RBAC roles, see Kubernetes RBAC user-facing roles.
User-facing roles
Default ClusterRole | Default ClusterRoleBinding | Description |
---|---|---|
cluster-admin | system:masters group | Allows super-user access, to perform any action on any resource. When used in a ClusterRoleBinding, this role gives full control over every resource in the cluster and in all namespaces. When used in a RoleBinding, it gives full control over every resource in the role binding's namespace, including the namespace itself. |
admin | None | Allows admin access, intended to be granted within a namespace using a role binding. If used in a role binding, allows read/write access to most resources in a namespace, including the capability to create roles and role bindings within the namespace. This role doesn't allow write access to resource quota or to the namespace itself. This role also doesn't allow write access to endpoints in clusters created using Kubernetes v1.22+. For more information, see Write Access for Endpoints. |
edit | None | Allows read/write access to most objects in a namespace. This role doesn't allow viewing or modifying roles or role bindings. However, this role allows accessing secrets and running pods as any ServiceAccount in the namespace, so it can be used to gain the API access levels of any ServiceAccount in the namespace. This role also doesn't allow write access to endpoints in clusters created using Kubernetes v1.22+. For more information, see Write Access for Endpoints. |
view | None | Allows read-only access to see most objects in a namespace. It doesn't allow viewing roles or role bindings. This role doesn't allow viewing secrets, since reading the contents of secrets enables access to ServiceAccount credentials in the namespace, which would allow API access as any ServiceAccount in the namespace (a form of privilege escalation). |
Use a built-in Kubernetes RBAC role with Microsoft Entra ID
To use a built-in Kubernetes RBAC role with Microsoft Entra ID, follow these steps:
Apply the built-in
view
Kubernetes RBAC role to your Microsoft Entra group:kubectl create clusterrolebinding <name of your cluster role binding> --clusterrole=view --group=<Azure AD group object ID>
Apply the built-in
view
Kubernetes RBAC role to each of your Microsoft Entra users:kubectl create clusterrolebinding <name of your cluster role binding> --clusterrole=view --user=<Azure AD user object ID>
Work with cluster resources using Microsoft Entra IDs
Now, test the expected permissions when you create and manage resources in a Kubernetes cluster. In these examples, you schedule and view pods in the user's assigned namespace. Then, you try to schedule and view pods outside the assigned namespace.
Sign in to Azure using the
$AKSDEV_ID
user account that you specified as an input to theaz ad group member add
command. Run theaz connectedk8s proxy
command to open a channel to the cluster:az connectedk8s proxy -n <cluster-name> -g <resource-group>
After the proxy channel is established, open another session, and schedule an NGINX pod using the
kubectl run
command in the dev namespace:kubectl run nginx-dev --image=mcr.microsoft.com/oss/nginx/nginx:1.15.5-alpine --namespace dev
When NGINX is successfully scheduled, you should see the following output:
pod/nginx-dev created
Now, use the
kubectl get pods
command to view pods in thedev
namespace:kubectl get pods --namespace dev
When NGINX is successfully running, you should see the following output:
NAME READY STATUS RESTARTS AGE nginx-dev 1/1 Running 0 4m
Create and view cluster resources outside the assigned namespace
To attempt to view pods outside the dev namespace, use the kubectl get pods
command with the --all-namespaces
flag:
kubectl get pods --all-namespaces
The user's group membership doesn't have a Kubernetes role that allows this action. Without the permission, the command generates an error:
Error from server (Forbidden): pods is forbidden: User cannot list resource "pods" in API group "" at the cluster scope