About Identity and Access Management

This topic explains how Tanzu Kubernetes Grid implements identity and access management.

Authentication

Tanzu Kubernetes Grid implements user authentication with Pinniped, an open-source authentication service for Kubernetes clusters. Pinniped allows you to plug external OpenID Connect (OIDC) or LDAP identity providers (IdP) into Tanzu Kubernetes (workload) clusters, so that you can control user access to those clusters. For LDAP authentication, Pinniped uses Dex as the endpoint to connect to your upstream LDAP IdP. If you use OIDC, Pinniped provides its own endpoint, so Dex is not required. Pinniped and Dex run automatically as in-cluster services in your management clusters if you enable identity management. For instructions on how to enable identity management in Tanzu Kubernetes Grid, see Configure Identity Management.

Authentication Flow

The authentication flow between the management and workload clusters includes the following:

  • The Tanzu Kubernetes Grid administrator enables and configures identity management on the management cluster, specifying an external LDAP or OIDC IdP.
  • Authentication service components are deployed into the management cluster, using the LDAP or OIDC IdP details specified by the administrator.
  • The administrator creates a Tanzu Kubernetes (workload) cluster. The workload cluster inherits the authentication configuration from the management cluster.
  • The administrator creates a role binding to associate a given user with a given role on the workload cluster.
  • The administrator provides the kubeconfig for the workload cluster to the user.
  • A user uses the kubeconfig to connect to the workload cluster, for example, by running kubectl get pods --kubeconfig.
  • The management cluster authenticates the user with the IdP.
  • The workload cluster either allows or denies the kubectl get pods request, depending on the permissions of the user’s role.

In the image below, the blue arrows represent the authentication flow between the workload cluster, the management cluster, and the external IdP. The green arrows represent Tanzu CLI and kubectl traffic between the workload cluster, the management cluster, and the external IdP.

Identity Management in Tanzu Kubernetes Grid

Identity Management Components

The diagram below shows the identity management components that Tanzu Kubernetes Grid deploys in the management cluster and in workload clusters when you enable identity management.

Identity Management architecture in Tanzu Kubernetes Grid

Understanding the diagram:

  • The purple-bordered rectangles show the identity management components, which include Pinniped, Dex, and a post-deployment job in the management cluster and Pinniped and a post-deployment job in the workload cluster. In Tanzu Kubernetes Grid v1.3.0, Pinniped uses Dex as the endpoint for both OIDC and LDAP providers. In v1.3.1 and later, Dex is deployed only for LDAP providers. If you configure an OIDC provider in v1.3.1 and later, Pinniped communicates with your provider directly, without going through Dex.

  • The gray-bordered rectangles show the components that Tanzu Kubernetes Grid uses to control the lifecycle of the identity management components, which include the Tanzu CLI, tanzu-addons-manager, and kapp-controller.

  • The green-bordered rectangle shows the Pinniped add-on secret created for the management cluster.

  • The orange-bordered rectangle in the management cluster shows the Pinniped add-on secret created for the workload cluster. The secret is mirrored to the workload cluster.

Internally, Tanzu Kubernetes Grid deploys the identity management components as an auto-managed package, pinniped. This package contains the pinniped add-on. When you deploy a management cluster with identity management enabled or enable it as a post-deployment step, the Tanzu CLI creates a Kubernetes secret for the pinniped add-on in the management cluster. tanzu-addons-manager reads the secret, which contains your IdP configuration information, and instructs kapp-controller to configure the pinniped add-on using the configuration information from the secret.

The Tanzu CLI creates a separate pinniped add-on secret for each workload cluster that you deploy from the management cluster. All secrets are stored in the management cluster. For more information, see Auto-Managed Packages.

Authorization

Tanzu Kubernetes Grid uses role-based access control (RBAC) authorization. For instructions on how to configure RBAC, see Configure RBAC.

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