A new version of Anthos GKE on AWS was released on August 5. See the release notes for information on breaking changes.

Authentication

GKE on AWS supports the following authentication methods:

Connect

To log in via Google Cloud Console with Connect, GKE on AWS can use a Kubernetes service account's bearer token. For more information, see Logging in to a cluster from Cloud Console.

The Kubernetes API server and the ID token

After authenticating with the cluster, you can interact using the kubectl CLI of Cloud SDK. When kubectl calls the Kubernetes API server on behalf of the user, the API server verifies the token by using the OpenID provider's public certificate. Then the API server parses the token to learn the user's identity and the user's security groups.

The API server determines whether the user is authorized to make this particular call by comparing the user's security groups to the cluster's role-based Access Control (RBAC) policy.

OIDC

This section assumes you are familiar with OAuth 2.0 and OpenID Connect. You should also be familiar with scopes and claims in the context of OpenID authentication.

Overview

With OIDC, you can manage access to a Kubernetes cluster with the standard procedures in your organization for creating, enabling, and disabling employee accounts. You can also use your organization's security groups to configure access to a Kubernetes cluster or to specific services in the cluster.

A typical OIDC login flow follows:

  • A user signs in to an OpenID provider by presenting a username and password.

  • The OpenID provider issues an ID token for the user. The token is signed by the provider.

  • The gcloud tool, acting on behalf of the user, sends an HTTPS request to the Kubernetes API server. The application includes the user's ID token in the request header.

  • The Kubernetes API server verifies the token by using the provider's certificate.

If your enterprise runs an Active Directory Federation Services (ADFS) server, the ADFS server could serve as your OpenID provider. Another option is to use a third party as your OpenID provider, For example, Google, Microsoft, Facebook, and Twitter are all OpenID providers.

Signing in with gcloud

You run the gcloud anthos auth login command to authenticate with your clusters. gcloud authenticates your request to the Kubernetes API server.

For this to work, your OIDC ID tokens must be stored in the kubeconfig file. You add tokens to your kubeconfig file with gcloud anthos create-login-config. GKE on AWS uses the gcloud CLI of Cloud SDK to request and obtain the ID token and other OIDC values in the kubeconfig file.